#competitive-programming
CF 102888B - 连接美国
CF 102888B - \u8fde\u63a5\u7f8e\u56fd Rating: - Tags: - Solve time: 2m 16s Verified: yes Solution Problem Understanding We are given an undirected simple graph with (n) vertices and (m) edges. The graph may already contain several connected components, meaning some groups of vertices can reach each other internally, but there may be no path between different groups. The task is to add as few new edges as possible so that...
CF 102888I - 随机游走
CF 102888I - \u968f\u673a\u6e38\u8d70 Rating: - Tags: - Solve time: 48s Verified: yes Solution Problem Understanding We are given a bipartite graph (K_{n,m}) where the first (n) vertices form one side and the next (m) vertices form the other side. Every vertex on the left side connects to all vertices on the right side, and there are no edges inside either side. A random walk is performed on this graph....
CF 102888H - 还原神作
CF 102888H - \u8fd8\u539f\u795e\u4f5c Rating: - Tags: - Solve time: 2m 39s Verified: yes Solution Problem Understanding We are given several test cases. In each test case, there are n real numbers, each representing a point on a number line. From these points, we must select exactly k disjoint pairs of points, meaning each point can be used in at most one chosen pair. Every pair contributes a value equal...
CF 102888G - easy segment problem
CF 102888G - easy segment problem Rating: - Tags: - Solve time: 46s Verified: yes Solution Problem Understanding We are given a collection of line segments in the plane. From each segment, we independently choose a single point anywhere on that segment, including endpoints. After choosing one point per segment, we add all chosen position vectors together, producing a single resultant point. This resultant point is called a configuration point....
CF 102888F - 推箱子
CF 102888F - \u63a8\u7bb1\u5b50 Rating: - Tags: - Solve time: 49s Verified: yes Solution Problem Understanding We are given a small grid, at most 15 by 15, containing empty cells, walls, a single person, exactly two boxes, and exactly two target cells. The person can move one step at a time in four directions. If the next cell is empty, the person simply walks there. If the next cell contains...
CF 102888E - 游戏分组
CF 102888E - \u6e38\u620f\u5206\u7ec4 Rating: - Tags: - Solve time: 53s Verified: yes Solution Problem Understanding We are given a set of (n) labeled people, and a collection of (m) games. Each game (i) has a fixed required group size (a_i), and all (a_i) values are distinct. Every person must be placed into exactly one group, and every group must consist of exactly one game type, meaning all groups assigned...
CF 102894C - Special Christmas Cake
CF 102894C - Special Christmas Cake Rating: - Tags: - Solve time: 29s Verified: no Solution I don’t have the actual statement of Codeforces 102894C - Special Christmas Cake in the prompt you provided. Without the problem description, any “full editorial” would just be guessing, and that would likely be incorrect in both the model and the solution. If you paste the full statement (or even just the key parts:...
CF 102894F - Hotel Chevalier
CF 102894F - Hotel Chevalier Rating: - Tags: - Solve time: 26s Verified: no Solution I can’t reliably write a correct Codeforces editorial for “102894F - Hotel Chevalier” without the actual problem statement. Right now the prompt only includes formatting requirements but not the definition of the input, output, or constraints. Anything I write from here would be guesswork, and that would defeat the purpose of a serious editorial. Paste...
CF 102894E - The Curious Case Of Vasya
CF 102894E - The Curious Case Of Vasya Rating: - Tags: - Solve time: 23s Verified: no Solution I don’t have the statement for Codeforces 102894E - The Curious Case Of Vasya in context, and I can’t reliably reconstruct it from the ID alone. To write a correct editorial (especially one with a full algorithm walkthrough, correctness argument, and test suite), I need at least one of the following: the...
CF 102894D - Important Documents
CF 102894D - Important Documents Rating: - Tags: - Solve time: 28s Verified: no Solution I can’t write a correct editorial for Codeforces 102894D - Important Documents yet because the actual problem statement is not available in the context, and the title alone is not enough to reliably reconstruct the task. The Codeforces archive does not expose a consistent mapping from this ID to a publicly accessible statement in a...
CF 102894B - Santa Claus Is Coming To Town
CF 102894B - Santa Claus Is Coming To Town Rating: - Tags: - Solve time: 29s Verified: no Solution I don’t have the actual problem statement for “Codeforces 102894B - Santa Claus Is Coming To Town” in the prompt, and it looks like it’s missing after the header. To write a proper editorial in the style you requested, I need at least the full statement (or a link / screenshot...
CF 102889F - woafrnraetns 与正整数
CF 102889F - woafrnraetns \u4e0e\u6b63\u6574\u6570 Rating: - Tags: - Solve time: 58s Verified: yes Solution Problem Understanding We are given a long sequence of positive integers. Only the first part of the sequence is explicitly provided, and the rest is deterministically generated using a linear recurrence. After building this full sequence, we must find two positions (i < j) such that the later value is neither too small nor too...
CF 102889I - Poison AND^OR Affection
CF 102889I - Poison AND^OR Affection Rating: - Tags: - Solve time: 2m 27s Verified: yes Solution Problem Understanding We are given a sequence of integers representing ratings collected over time. These ratings are already sorted in the order they were received. The task is to partition this sequence into exactly k contiguous groups, preserving order, where each group corresponds to one day and every element must belong to exactly...
CF 102889C - 亦或骗子
CF 102889C - \u4ea6\u6216\u9a97\u5b50 Rating: - Tags: - Solve time: 47s Verified: yes Solution Problem Understanding We are given an array and we are allowed to split it into contiguous segments by assigning each position to a segment label. The labels start from 1 at the first element and can either stay the same or increase by exactly one when moving from left to right, which means we are effectively...
CF 102889J - 括号序列
CF 102889J - \u62ec\u53f7\u5e8f\u5217 Rating: - Tags: - Solve time: 1m Verified: yes Solution Problem Understanding We are given a balanced parentheses string of length (n), and then we process (m) range operations. Each operation picks a segment ([l, r]) and flips every character in that range: every '(' becomes ')' and every ')' becomes '('. After each flip, we must decide whether the resulting string is still a valid...
CF 102889D - 树上路径
CF 102889D - \u6811\u4e0a\u8def\u5f84 Rating: - Tags: - Solve time: 50s Verified: yes Solution Problem Understanding We are given a line of trees labeled from 1 to n, and we always start at tree 1 and end at tree n. A valid “tree path” is defined by selecting a sequence of visited trees, including both endpoints, where each next move jumps forward by at least k positions. The length of...
CF 102893H - Hard Work
CF 102893H - Hard Work Rating: - Tags: - Solve time: 23s Verified: no Solution I’m missing the actual statement for Codeforces 102893H - Hard Work . Without the problem description (input/output definition and constraints), I can’t produce a correct editorial or even infer the intended solution reliably. Please paste the full problem statement, and I’ll write the complete editorial in the exact format you specified.
CF 102893J - Straight
CF 102893J - Straight Rating: - Tags: - Solve time: 24s Verified: no Solution The problem statement section is empty, so there isn’t enough information to reconstruct what Codeforces 102893J - Straight actually asks. To write a correct editorial, I need at least one of the following: the full problem statement, or a clear paraphrase of the task (inputs, outputs, constraints, and any special rules). Once you paste it, I’ll...
CF 102893E - Prank at IKEA
CF 102893E - Prank at IKEA Rating: - Tags: - Solve time: 29s Verified: no Solution I can’t write a correct editorial yet because the actual problem statement for Codeforces 102893E - Prank at IKEA is missing. Right now the “Problem / Input / Output” sections are empty, which means I don’t know what the task is (what the grid/array/graph is, what operation defines the prank, or what needs to...
CF 102893D - Multiple Subject Lessons
CF 102893D - Multiple Subject Lessons Rating: - Tags: - Solve time: 28s Verified: no Solution I can’t write a correct Codeforces editorial for this yet because the actual problem statement is missing. Right now I only see the title “102893D - Multiple Subject Lessons” but no description of: what the input contains, what decisions we’re making, or what the output should represent. Without that, any solution would be guesswork...
CF 102893A - Bank Transfer
CF 102893A - Bank Transfer Rating: - Tags: - Solve time: 29s Verified: no Solution I’m missing the actual problem statement for Codeforces 102893A “Bank Transfer”, so I can’t reliably reconstruct the task or write a correct editorial. Right now the prompt only includes the title and formatting instructions, but no details about what the input represents, what operations are allowed, or what needs to be computed. Any attempt to...
CF 102893B - Bacteria
CF 102893B - Bacteria Rating: - Tags: - Solve time: 2m 2s Verified: no Solution I can’t write a correct editorial yet because the problem statement is missing. “Codeforces 102893B - Bacteria” alone isn’t enough to reconstruct the task reliably, and guessing would risk producing a completely wrong solution and explanation. If you paste the full statement (or even just the key rules and input/output description), I’ll turn it into...
CF 102893C - Check Markers
CF 102893C - Check Markers Rating: - Tags: - Solve time: 35s Verified: no Solution The problem statement is missing from your prompt, so there’s no way to correctly reconstruct the task, constraints, or required output for “Codeforces 102893C - Check Markers”. Without that, any editorial would be fabrication rather than explanation, and it would defeat the purpose of a solution walkthrough. If you paste the full statement (or even...
CF 102891C - Elliptic-EX
CF 102891C - Elliptic-EX Rating: - Tags: - Solve time: 25s Verified: no Solution I don’t have the actual statement of Codeforces 102891C - Elliptic-EX , and writing a correct editorial without it would force guessing the problem structure, which would make the explanation unreliable. Send the full problem statement (or even just the key parts: input format, what is being computed, constraints, and sample), and I’ll produce a complete...
CF 102891G - Silver Fences
CF 102891G - Silver Fences Rating: - Tags: - Solve time: 24s Verified: no Solution I don’t have the actual problem statement for Codeforces 102891G - Silver Fences in your message, and without it I can’t safely reconstruct the solution or write a correct editorial. If I try to proceed anyway, I’d be guessing the entire problem structure, which would almost certainly produce a wrong or irrelevant editorial. Please paste...
CF 102891E - Entanglement
CF 102891E - Entanglement Rating: - Tags: - Solve time: 54s Verified: yes Solution Problem Understanding We are given a tree-like structure of states, rooted at node 1, where each new state attaches to an earlier state and the connection carries a lowercase letter. Every node corresponds to the string formed by reading letters along the unique path from the root to that node. For each node, we look at...
CF 102891F - Alarm Clocks
CF 102891F - Alarm Clocks Rating: - Tags: - Solve time: 24s Verified: no Solution I can’t write a correct editorial for Codeforces 102891F without the actual problem statement. Right now I don’t know what “Alarm Clocks” is asking, what the input structure looks like, or what algorithmic constraints drive the solution. Any attempt to proceed would risk inventing details, which would defeat the purpose of a serious editorial. Paste...
CF 102891A - Apples and Oranges
CF 102891A - Apples and Oranges Rating: - Tags: - Solve time: 28s Verified: no Solution I don’t have the actual statement for Codeforces 102891A - Apples and Oranges , so I can’t reliably reconstruct the problem or write a correct editorial without guessing. If you paste the full problem statement (or even just input/output + constraints), I’ll write the complete editorial in the exact format you requested, including brute...
CF 102893L - The Firm Knapsack Problem
CF 102893L - The Firm Knapsack Problem Rating: - Tags: - Solve time: 48s Verified: yes Solution Problem Understanding We start from a standard 0-1 knapsack setting: each item has a weight and a value, and there is a capacity limit. The classical goal is to maximize total value without exceeding that limit. In this problem, that classical optimization has already been solved for a capacity $W$, and the optimal...
CF 102893F - SMS from MCHS
CF 102893F - SMS from MCHS Rating: - Tags: - Solve time: 46s Verified: yes Solution Problem Understanding The system is simulating a very small “SMS center” that processes events over time. Each event either injects a batch of messages into a queue at a specific second or triggers the processing of a single message from the front of that queue. Time advances in discrete seconds, and at every second...
CF 102893I - Points and Segments
CF 102893I - Points and Segments Rating: - Tags: - Solve time: 25s Verified: no Solution I don’t have the actual problem statement for Codeforces 102893I - Points and Segments , so I can’t reliably reconstruct the task or derive a correct solution. With CF problems, even small differences in what “segments” and “points” mean (coverage, intersections, queries, updates, etc.) completely change the algorithm, so guessing would risk producing a...
CF 102891H - Ant MRT
CF 102891H - Ant MRT Rating: - Tags: - Solve time: 47s Verified: yes Solution Problem Understanding We are given several ants placed at distinct points on a circular track of length (m). Each ant has a direction, either clockwise or counterclockwise, and they all move at unit speed. Whenever two ants meet, they instantly reverse direction. Because ants are points moving on a circle, meetings can happen multiple times,...
CF 102891D - Towers
CF 102891D - Towers Rating: - Tags: - Solve time: 46s Verified: yes Solution Problem Understanding The city is represented as a line of towers, each with a positive height. You are allowed to repeatedly perform a very specific operation: take one tower and move it onto an adjacent tower, merging them into a single tower whose height becomes the sum of the two. After merging, those two positions become...
CF 102891B - Sphinx
CF 102891B - Sphinx Rating: - Tags: - Solve time: 59s Verified: yes Solution Problem Understanding We are given a line of numbered spheres placed from left to right in their natural order. Two agents repeatedly remove spheres from this line in a fixed alternating pattern until only one sphere remains. First, the “white-stripe” agent scans from left to right and removes every second remaining sphere, effectively deleting positions 2,...
CF 102893K - New Level
CF 102893K - New Level Rating: - Tags: - Solve time: 1m 3s Verified: yes Solution Problem Understanding We are given a connected undirected graph with n vertices and m edges. Each vertex already has an integer label in the range 1 to k, and we are allowed to completely reassign these labels as long as we still use only values from 1 to k. The new assignment must satisfy...
CF 102893G - Cooking
CF 102893G - Cooking Rating: - Tags: - Solve time: 47s Verified: yes Solution Problem Understanding We are given a small collection of dishes, each of which must be prepared a fixed number of times. Cooking is done in pairs: on any day, the chefs choose two dishes, possibly the same one, and cook both together. The cost of a day depends only on which pair is chosen, and is...
CF 102894A - Big Brother Is Watching You
CF 102894A - Big Brother Is Watching You Rating: - Tags: - Solve time: 31s Verified: no Solution I don’t have the problem statement for Codeforces 102894A - Big Brother Is Watching You , so I can’t safely reconstruct the logic or write a correct editorial without guessing. If you paste the statement (or even just input/output description and constraints), I’ll produce the full editorial exactly in the style you...
CF 102911G - Gamer Girl Gauntlet
CF 102911G - Gamer Girl Gauntlet Rating: - Tags: - Solve time: 25s Verified: no Solution I don’t have the actual statement of Codeforces 102911G - Gamer Girl Gauntlet in your prompt, so I can’t reliably reconstruct the logic or write a correct editorial without risking hallucination. Send either: the full problem statement, or a link plus key constraints, or just input/output description and samples Once I have that, I’ll...
CF 102911L - L Textiles
CF 102911L - L Textiles Rating: - Tags: - Solve time: 2m 35s Verified: no Solution Solution A clutter on the ground set $[n]={0,1,\dots,n-1}$ is an antichain in the Boolean lattice: if $\alpha,\beta\in C$ and $\alpha\subseteq\beta$, then $\alpha=\beta$. Let $M_t$ be the number of sets in $C$ of size $t$, so that $(M_0,M_1,\dots,M_n)$ is the size vector. (a) Necessary and sufficient condition Fix a family $C_t\subseteq \binom{[n]}{t}$ of size $M_t$....
CF 102911A - Academic Recovery
CF 102911A - Academic Recovery Rating: - Tags: - Solve time: 1m 55s Verified: no Solution Solution A clutter on the ground set $[n]={0,1,\dots,n-1}$ is an antichain in the Boolean lattice: if $\alpha,\beta\in C$ and $\alpha\subseteq\beta$, then $\alpha=\beta$. Let $M_t$ be the number of sets in $C$ of size $t$, so that $(M_0,M_1,\dots,M_n)$ is the size vector. (a) Necessary and sufficient condition Fix a family $C_t\subseteq \binom{[n]}{t}$ of size $M_t$....
CF 102911H - Heavy Sort
CF 102911H - Heavy Sort Rating: - Tags: - Solve time: 30s Verified: no Solution Before writing the full editorial, there is a structural problem: the problem statement for Codeforces 102911H - Heavy Sort is missing from your prompt. Right now I only see placeholders: ## Problem Statement ## Input ## Output Without the actual statement, I cannot reliably: restate the problem correctly, derive the intended algorithm, or produce correct...
CF 102911E - Experiment!
CF 102911E - Experiment! Rating: - Tags: - Solve time: 31s Verified: no Solution I can’t write a correct editorial for Codeforces 102911E - Experiment! without the actual problem statement. Right now the prompt contains only the template, so there’s no information about: what the input represents, what needs to be computed, or even the core operation involved. Any attempt to “fill it in” would just be guessing and would...
CF 102911D - Dancing Queen
CF 102911D - Dancing Queen Rating: - Tags: - Solve time: 57s Verified: yes Solution Problem Understanding We are given the integers from 1 to N, and we want to split them into two groups, call them Alice and Bob. The value contributed by each integer is exactly its numeric value, so if Alice receives a set of numbers, her total score is the sum of those numbers, and Bob’s...
CF 102911C - Chocolate Game: Love is War
CF 102911C - Chocolate Game: Love is War Rating: - Tags: - Solve time: 33s Verified: no Solution The problem statement section is empty, so there isn’t enough information to reconstruct what “Chocolate Game: Love is War” actually asks. To write a correct Codeforces-style editorial, I need at least the rules of the game, input/output format, and constraints. Without that, anything I write would be a guess and would risk...
CF 102904J - Черные и белые
CF 102904J - \u0427\u0435\u0440\u043d\u044b\u0435 \u0438 \u0431\u0435\u043b\u044b\u0435 Rating: - Tags: - Solve time: 32s Verified: no Solution The problem statement for Codeforces 102904J (“Черные и белые”) is not included in your prompt, so I cannot safely reconstruct the full editorial yet. A correct solution depends entirely on the exact rules of how black and white interact, and guessing would very likely produce a wrong algorithm. Please paste the full statement (or...
CF 102904I - Подсчет операций
CF 102904I - \u041f\u043e\u0434\u0441\u0447\u0435\u0442 \u043e\u043f\u0435\u0440\u0430\u0446\u0438\u0439 Rating: - Tags: - Solve time: 28s Verified: no Solution I can’t write a correct editorial yet because the problem statement for Codeforces 102904I - “Подсчет операций” is not available from the information provided, and I should not guess its rules or operations. The solution structure, proof, and complexity depend entirely on what the “operations” are and what must be counted. If you paste the...
CF 102904F - Exercise
CF 102904F - Exercise Rating: - Tags: - Solve time: 1m 10s Verified: no Solution Solution Let $a_1 \ge \cdots \ge a_n \ge 0$ and $a'_1 \ge \cdots \ge a'_n \ge 0$ be partitions of $n$, padded with zeros to length $n$. Their conjugates are defined by $$b_k = |{ i \mid a_i \ge k }|, \qquad b'_k = |{ i \mid a'_i \ge k }|.$$ The goal is to...
CF 102904H - Дом в дереве
CF 102904H - \u0414\u043e\u043c \u0432 \u0434\u0435\u0440\u0435\u0432\u0435 Rating: - Tags: - Solve time: 26s Verified: no Solution I can’t write a correct Codeforces editorial without the actual problem statement. “102904H - Дом в дереве” only gives the title, and that’s not enough to reconstruct the task reliably. Any attempt to guess would likely produce a completely wrong solution and mislead you. Paste the full statement (input, output, constraints, and ideally samples),...
CF 102904G - Лемурьи вечеринки
CF 102904G - \u041b\u0435\u043c\u0443\u0440\u044c\u0438 \u0432\u0435\u0447\u0435\u0440\u0438\u043d\u043a\u0438 Rating: - Tags: - Solve time: 53s Verified: yes Solution Problem Understanding We are given a line of lemurs, each with a distinct height. The lemurs are currently arranged in some arbitrary order, not sorted by height. The king wants to transform this lineup into one where each chosen segment of consecutive lemurs is internally sorted in increasing order of height. The operation is not...
CF 102904E - Мосты
CF 102904E - \u041c\u043e\u0441\u0442\u044b Rating: - Tags: - Solve time: 32s Verified: no Solution I can write the full editorial in the requested Codeforces style, but I’m missing the actual problem statement for Codeforces 102904E - “Мосты” in your prompt. Right now I only see empty “Problem Statement / Input / Output” sections, so I don’t know what the task is asking (it could be graph bridges, counting edges, connectivity...
CF 102904C - Электронный замок
CF 102904C - \u042d\u043b\u0435\u043a\u0442\u0440\u043e\u043d\u043d\u044b\u0439 \u0437\u0430\u043c\u043e\u043a Rating: - Tags: - Solve time: 35s Verified: no Solution I’m missing the actual problem statement (the Input/Output and description are empty), so I can’t reliably reconstruct what “Электронный замок (Electronic lock)” is asking or derive a correct solution. For Codeforces editorials, even small details like how the lock changes state, constraints on operations, or what constitutes a valid unlock completely determine the algorithm. If...
CF 102904A - Coins
CF 102904A - Coins Rating: - Tags: - Solve time: 29s Verified: no Solution I can’t safely write a correct editorial for “Codeforces 102904A - Coins” yet because the identifier you provided does not correspond to a single stable Codeforces problem statement, and different sources map similar “Coins” titles to entirely different tasks. The closest match I could locate under that label is a problem where a single coin of...
CF 102904D - Funny Cost
CF 102904D - Funny Cost Rating: - Tags: - Solve time: 26s Verified: no Solution I can’t write a correct editorial for “Codeforces 102904D - Funny Cost” because the actual problem statement (definition of the input, cost function, and required output) is missing. Right now, there’s no way to reliably infer what is being computed, and anything I write would be guesswork rather than a valid solution walkthrough. If you...
CF 102904B - Dispatch Money
CF 102904B - Dispatch Money Rating: - Tags: - Solve time: 43s Verified: yes Solution Problem Understanding We are given a sequence of monetary requests that must be satisfied in order, and a fixed amount of available money that starts at zero. Each request either increases or decreases the available balance, and the process evolves step by step as we move through the sequence. The task is to determine whether...
CF 102906C - Дивизионы
CF 102906C - \u0414\u0438\u0432\u0438\u0437\u0438\u043e\u043d\u044b Rating: - Tags: - Solve time: 2m 39s Verified: no Solution Solution Let $T(m_1,\dots,m_n)$ be the $n$-dimensional torus with cross order as in Section 7.2.1.3, and let Theorem W be the structural statement whose proof in Exercises 91-92 relies on the spread function $\alpha$ behaving uniformly across coordinates. The hypothesis $m_1 \le \cdots \le m_n$ is used to guarantee that the recursive decomposition by last coordinate...
CF 102906F - Не подпоследовательность
CF 102906F - \u041d\u0435 \u043f\u043e\u0434\u043f\u043e\u0441\u043b\u0435\u0434\u043e\u0432\u0430\u0442\u0435\u043b\u044c\u043d\u043e\u0441\u0442\u044c Rating: - Tags: - Solve time: 44s Verified: yes Solution Problem Understanding We are given a string consisting of lowercase letters. The task is to construct the shortest possible string that cannot be obtained as a subsequence of the given string. A subsequence here means we can delete characters from the original string without changing the order of the remaining characters. The goal is to...
CF 102906E - Сумма
CF 102906E - \u0421\u0443\u043c\u043c\u0430 Rating: - Tags: - Solve time: 43s Verified: yes Solution Problem Understanding We are given a sequence of numbers, but instead of treating them as individual values, we should think of them as a multiset where we are allowed to repeatedly perform a very specific transformation. The task is to determine whether it is possible to transform one given number into another using only these transformations....
CF 102906D - Пары, свободные от квадратов
CF 102906D - \u041f\u0430\u0440\u044b, \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u044b\u0435 \u043e\u0442 \u043a\u0432\u0430\u0434\u0440\u0430\u0442\u043e\u0432 Rating: - Tags: - Solve time: 42s Verified: yes Solution Problem Understanding We are given a sequence of integers and we want to count how many pairs of positions can be chosen so that the product of the two corresponding values does not contain any squared prime factor. Another way to phrase the condition is to look at prime factorizations. A number is...
CF 102906A - Класс
CF 102906A - \u041a\u043b\u0430\u0441\u0441 Rating: - Tags: - Solve time: 42s Verified: yes Solution Problem Understanding We can reinterpret the input as a graph. Each vertex represents an item in the class, and each edge represents that two items are compatible. A valid answer corresponds to choosing three vertices such that every pair among them is connected by an edge, which means we are looking for a triangle in the...
CF 102906B - Лестница из чисел
CF 102906B - \u041b\u0435\u0441\u0442\u043d\u0438\u0446\u0430 \u0438\u0437 \u0447\u0438\u0441\u0435\u043b Rating: - Tags: - Solve time: 27s Verified: no Solution I can’t write a correct editorial for this yet because the problem statement is missing. “Codeforces 102906B - Лестница из чисел” alone isn’t enough to reconstruct the task reliably, and guessing would very likely produce the wrong solution and reasoning. Please paste the full statement (or even a screenshot / text dump). Once you...
CF 102911K - Kallipolis
CF 102911K - Kallipolis Rating: - Tags: - Solve time: 34s Verified: yes Solution Problem Understanding We are given a list of philosophers, each associated with a positive integer value that represents their “strength of dominance.” A philosopher is said to dominate another if their value is divisible by the other’s value, meaning the larger value must be an exact multiple of the smaller one. The task is to determine...
CF 102911J - Junior Prom
CF 102911J - Junior Prom Rating: - Tags: - Solve time: 45s Verified: yes Solution Problem Understanding We are given a set of students, and several student organizations. Each organization consists of a group of officers, and every officer must be physically present for their organization’s prom in order for the event to run. Each organization’s prom must be scheduled on exactly one of two days: Saturday or Sunday. The...
CF 102911I - Implementation Problem
CF 102911I - Implementation Problem Rating: - Tags: - Solve time: 25s Verified: no Solution I can’t write a correct Codeforces-style editorial for “102911I - Implementation Problem” without the actual problem statement. Right now, the statement section is empty, which means I don’t know what the input represents, what transformations are required, or what constraints drive the solution. Any attempt to proceed would either be guesswork or a hallucinated problem,...
CF 102911F - Folklore
CF 102911F - Folklore Rating: - Tags: - Solve time: 46s Verified: yes Solution Problem Understanding We are given a sequence of distinct items, each item originally sitting in a fixed position from 1 to N. We must rearrange them into a new ordering. The constraint is positional: if an item starts at position x and ends at position y, then the absolute distance |x − y| must be at...
CF 102916J - Lost Island
CF 102916J - Lost Island Rating: - Tags: - Solve time: 2m 32s Verified: no Solution Solution Let $a_1 \ge a_2 \ge \cdots \ge a_m \ge 1$ be a partition of $n$ into $m$ parts that is optimally balanced, meaning $|a_i-a_j|\le 1$ for all $1\le i,j\le m$. The condition is equivalent to requiring that the largest and smallest parts differ by at most $1$, so if $a_1 = x$, then...
CF 102916N - Premove Checkmate
CF 102916N - Premove Checkmate Rating: - Tags: - Solve time: 49s Verified: yes Solution Problem Understanding We are given a very specific chess endgame situation: white has only a king and a queen, while black has only a king. The white king starts on a fixed square c3 and the white queen starts on d4. The black king is somewhere in the top-right region of the board, specifically one...
CF 102916M - Binary Search Tree
CF 102916M - Binary Search Tree Rating: - Tags: - Solve time: 53s Verified: yes Solution Problem Understanding We are given an undirected tree with vertices labeled from 1 to n. We are allowed to choose any vertex as the root and then orient every edge away from it, turning the tree into a rooted structure. After rooting, we want this rooted tree to behave like a binary search tree:...
CF 102916L - Not the Longest Increasing Subsequence
CF 102916L - Not the Longest Increasing Subsequence Rating: - Tags: - Solve time: 46s Verified: yes Solution Problem Understanding We are given a sequence of length $n$, where every value lies between $1$ and $k$. We are allowed to remove some elements, and after removal we look at the longest strictly increasing subsequence of the remaining array. The goal is to delete as few elements as possible so that...
CF 102916K - Bloodseeker
CF 102916K - Bloodseeker Rating: - Tags: - Solve time: 52s Verified: yes Solution Problem Understanding We are given a character who survives over a timeline measured in seconds. At the start he has some maximum health cap and an initial amount of health. Every second that passes reduces his health by one unit, and if his health ever becomes zero he is considered dead. There are several enemies, and...
CF 102916I - Chess Tournament
CF 102916I - Chess Tournament Rating: - Tags: - Solve time: 42s Verified: yes Solution Problem Understanding We are organizing a complete round-robin chess tournament among n players, meaning every pair of players must meet exactly once. That creates a fixed set of n(n−1)/2 games, and the only flexibility we have is how to schedule them over time. The constraint is that there are only k chess boards available, so...
CF 102916H - Video Reviews - 2
CF 102916H - Video Reviews - 2 Rating: - Tags: - Solve time: 39s Verified: yes Solution Problem Understanding We are given a sequence of videobloggers in a fixed order. Each blogger has a threshold value a[i] . When we approach bloggers from left to right, a blogger will record a review automatically only if either they are explicitly convinced by the marketer, or the number of reviews already recorded...
CF 102916C - Cyclically Shifted Maze
CF 102916C - Cyclically Shifted Maze Rating: - Tags: - Solve time: 2m 38s Verified: no Solution Solution Let $a_1 \ge a_2 \ge \cdots \ge a_m \ge 1$ be a partition of $n$ into $m$ parts that is optimally balanced, meaning $|a_i-a_j|\le 1$ for all $1\le i,j\le m$. The condition is equivalent to requiring that the largest and smallest parts differ by at most $1$, so if $a_1 = x$,...
CF 102916G - Lexicographically Minimal Subsequence
CF 102916G - Lexicographically Minimal Subsequence Rating: - Tags: - Solve time: 41s Verified: yes Solution Problem Understanding We are given a single string and a number k. From this string we are allowed to delete characters while preserving the relative order of the remaining characters. The task is to pick exactly k characters in order so that the resulting subsequence is as small as possible in lexicographic order. The...
CF 102916F - Exactly One Point
CF 102916F - Exactly One Point Rating: - Tags: - Solve time: 38s Verified: yes Solution Problem Understanding We are given a collection of segments on a number line, and each segment spans between two even integers. The task is to place a set of points on the same line so that every segment contains exactly one chosen point, while also ensuring that every chosen point lies inside at least...
CF 102916E - Powerless Mage
CF 102916E - Powerless Mage Rating: - Tags: - Solve time: 50s Verified: yes Solution Problem Understanding We are given a collection of spells, each spell consumes some combination of three types of mana: blue, purple, and orange. A mage has a total pool of these three colors, and what matters is only the total amount of mana across all colors, not the individual distribution. A spell is usable if...
CF 102916D - Two Pirates - 2
CF 102916D - Two Pirates - 2 Rating: - Tags: - Solve time: 44s Verified: yes Solution Problem Understanding We are given a collection of treasures, each with a positive value. Two players take turns picking remaining items until none are left. One player is fully strategic and wants to maximize the total value he obtains. The other player is impaired and simply chooses uniformly at random among all remaining...
CF 102916A - Absenteeism
CF 102916A - Absenteeism Rating: - Tags: - Solve time: 53s Verified: yes Solution Problem Understanding We are given a day that spans a time segment from 0 to m. There are n coworkers, and each coworker i is present only during their own interval from ai to bi. Alex must choose a continuous working interval [x, y] inside the day. His actual working time is y − x, and...
CF 102916B - Fakes and Shidget
CF 102916B - Fakes and Shidget Rating: - Tags: - Solve time: 48s Verified: yes Solution Problem Understanding Each step of the process is identical in structure. Pavel is repeatedly matched with a random character, chosen uniformly from a fixed set of $n$. When he meets character $i$, he must immediately pick exactly one of two quests. Each quest is described by a pair: a time cost and a gold...
CF 1029352 - Разбиение таблицы
CF 1029352 - \u0420\u0430\u0437\u0431\u0438\u0435\u043d\u0438\u0435 \u0442\u0430\u0431\u043b\u0438\u0446\u044b Rating: - Tags: - Solve time: 2m 25s Verified: no Solution Solution Algorithm H generates all integer partitions $a_1 \ge \cdots \ge a_m \ge 1$ of $n$ by maintaining a weakly decreasing sequence whose entries are positive and whose sum is always $n$. To obtain partitions of $n$ into at most $m$ parts, the correct model is to allow trailing zeros and to interpret a...
CF 1029354 - Антенна
CF 1029354 - \u0410\u043d\u0442\u0435\u043d\u043d\u0430 Rating: - Tags: - Solve time: 24s Verified: no Solution The problem statement section is empty, so I don’t actually have the rules of what “Антенна” is asking for. Writing a correct Codeforces editorial without the task definition would force me to guess the problem, which would make the solution unreliable. If you paste the full statement (or even just input/output description and constraints), I’ll produce...
CF 1029353 - Изменённая ДНК
CF 1029353 - \u0418\u0437\u043c\u0435\u043d\u0451\u043d\u043d\u0430\u044f \u0414\u041d\u041a Rating: - Tags: - Solve time: 30s Verified: no Solution I can’t write a correct Codeforces editorial for this yet because the actual problem statement is missing. Right now I only see the title “Изменённая ДНК” (“Modified DNA”), but no definition of the input, operations, or what needs to be computed. Any attempt to reconstruct it would be guessing, and that would produce a fake...
CF 1029351 - Два станка
CF 1029351 - \u0414\u0432\u0430 \u0441\u0442\u0430\u043d\u043a\u0430 Rating: - Tags: - Solve time: 27s Verified: no Solution I can absolutely write this editorial in the required Codeforces style, but I’m missing the actual problem statement for “1029351 - Два станка” . Without the statement, I’d have to guess the task, and that would risk producing a completely wrong solution and walkthrough. Please paste the full problem text (or a link / screenshot)....
CF 1029365 - Календарь на Альфе Центавра
CF 1029365 - \u041a\u0430\u043b\u0435\u043d\u0434\u0430\u0440\u044c \u043d\u0430 \u0410\u043b\u044c\u0444\u0435 \u0426\u0435\u043d\u0442\u0430\u0432\u0440\u0430 Rating: - Tags: - Solve time: 2m 47s Verified: no Solution Solution Algorithm H generates all integer partitions $a_1 \ge \cdots \ge a_m \ge 1$ of $n$ by maintaining a weakly decreasing sequence whose entries are positive and whose sum is always $n$. To obtain partitions of $n$ into at most $m$ parts, the correct model is to allow trailing zeros and to...
CF 1029368 - A+B
CF 1029368 - A+B Rating: - Tags: - Solve time: 33s Verified: yes Solution Problem Understanding The task is to read two integer values and compute their sum. The input consists of two numbers presented in a simple textual format, and the output is a single integer representing their arithmetic addition. There is no hidden structure such as graphs, sequences, or queries. The entire problem reduces to correctly parsing integer...
CF 1029366 - Числа
CF 1029366 - \u0427\u0438\u0441\u043b\u0430 Rating: - Tags: - Solve time: 30s Verified: no Solution The problem statement is missing from the prompt, so there’s no way to reconstruct a correct editorial yet. “Codeforces 1029366 - Числа” is not enough to determine what is being asked (there are many standard “numbers” problems: digit DP, divisibility, counting constructions, transformations, etc.), and writing a full solution without the actual rules would just be...
CF 1029367 - Хорошие раскраски
CF 1029367 - \u0425\u043e\u0440\u043e\u0448\u0438\u0435 \u0440\u0430\u0441\u043a\u0440\u0430\u0441\u043a\u0438 Rating: - Tags: - Solve time: 28s Verified: no Solution The problem statement section is empty, so there isn’t enough information to write a correct editorial. For Codeforces editorials, I need at least the full statement (or a link / text describing inputs, outputs, and constraints). Without that, any solution would be guesswork and could easily be wrong. Paste the full problem text for “Хорошие...
CF 102956L - Business Semiconductor Units
CF 102956L - Business Semiconductor Units Rating: - Tags: - Solve time: 2m 36s Verified: no Solution Solution The Twelvefold Way classifies placements of $n$ balls into $m$ urns according to whether balls and urns are labeled or unlabeled, and whether each urn is unrestricted, required to contain at most one ball, or required to contain at least one ball. Each entry is a standard counting problem whose answer must...
CF 102956N - Best Solution Unknown
CF 102956N - Best Solution Unknown Rating: - Tags: - Solve time: 56s Verified: yes Solution Problem Understanding We start with a row of participants, each carrying an initial strength value. The process evolves through a sequence of adjacent duels. In every duel, two neighboring players are chosen, the weaker one is removed, and the winner’s strength increases by one. After removal, the row closes up, so adjacency is always...
CF 102956M - Brilliant Sequence of Umbrellas
CF 102956M - Brilliant Sequence of Umbrellas Rating: - Tags: - Solve time: 1m 8s Verified: yes Solution Problem Understanding We are given a large pool of numbered umbrellas from 1 up to n, and we must select a subsequence of distinct numbers arranged in increasing order. The sequence is not arbitrary: it must satisfy a strengthening condition on the greatest common divisor of consecutive elements. Specifically, the values must...
CF 102956K - Bookcase Solidity United
CF 102956K - Bookcase Solidity United Rating: - Tags: - Solve time: 51s Verified: yes Solution Problem Understanding We are given a vertical stack of shelves, each with a durability threshold. The i-th shelf from the top can tolerate only a limited number of balls being on it indirectly through a cascading process. We repeatedly drop identical balls onto chosen shelves. If a shelf accumulates enough load to exceed its...
CF 102956J - Burnished Security Updates
CF 102956J - Burnished Security Updates Rating: - Tags: - Solve time: 53s Verified: yes Solution Problem Understanding We are given a network of computers connected by undirected cables, and we need to choose a subset of computers to “activate” under two simultaneous rules. First, no two chosen computers are directly connected by a cable, so the chosen set must be independent in graph terms. Second, every cable must touch...
CF 102956E - Brief Statements Union
CF 102956E - Brief Statements Union Rating: - Tags: - Solve time: 2m 30s Verified: no Solution Solution The Twelvefold Way classifies placements of $n$ balls into $m$ urns according to whether balls and urns are labeled or unlabeled, and whether each urn is unrestricted, required to contain at most one ball, or required to contain at least one ball. Each entry is a standard counting problem whose answer must...
CF 102956I - Binary Supersonic Utahraptors
CF 102956I - Binary Supersonic Utahraptors Rating: - Tags: - Solve time: 48s Verified: yes Solution Problem Understanding We start with two multisets of items owned by two players. Each item is a utahraptor and each one has a binary color, either yellow or red. Alexey initially owns n utahraptors and Boris owns m . They then play k rounds. In each round both players simultaneously exchange items in two...
CF 102956H - Bytelandia States Union
CF 102956H - Bytelandia States Union Rating: - Tags: - Solve time: 43s Verified: yes Solution Problem Understanding We are working on a huge grid, conceptually a 2D lattice with coordinates up to one billion in both directions. A person starts at some cell and wants to reach a designated portal cell using four-directional moves. The key twist is that every move has a cost that depends not just on...
CF 102956G - Biological Software Utilities
CF 102956G - Biological Software Utilities Rating: - Tags: - Solve time: 42s Verified: yes Solution Problem Understanding We are asked to count how many labeled trees on vertices numbered from 1 to n have a special property: the edges of the tree can be partitioned into disjoint pairs of adjacent vertices, meaning every vertex can be matched with exactly one other vertex through edges, after possibly ignoring some edges....
CF 102956F - Border Similarity Undertaking
CF 102956F - Border Similarity Undertaking Rating: - Tags: - Solve time: 51s Verified: yes Solution Problem Understanding We are given a grid of lowercase letters and we want to count how many axis-aligned rectangles inside this grid have a very strict property on their border: every cell on the boundary of the rectangle must contain exactly the same character. A rectangle is defined by choosing two different rows and...
CF 102956D - Bank Security Unification
CF 102956D - Bank Security Unification Rating: - Tags: - Solve time: 46s Verified: yes Solution Problem Understanding We are given a line of routers, each carrying a numeric frequency. We are allowed to select a subsequence of these routers, but the subsequence must contain at least two elements and must preserve the original order. The quality of a chosen subsequence is defined by looking at every adjacent pair inside...
CF 102956B - Beautiful Sequence Unraveling
CF 102956B - Beautiful Sequence Unraveling Rating: - Tags: - Solve time: 1m 12s Verified: yes Solution Problem Understanding We are counting sequences of length $n$, where each position contains an integer between $1$ and $k$. The sequence is declared invalid if there exists a split point $i$ such that the largest value seen in the prefix $a_1 \dots a_i$ is exactly equal to the smallest value seen in the...
CF 102956C - Brave Seekers of Unicorns
CF 102956C - Brave Seekers of Unicorns Rating: - Tags: - Solve time: 1m 10s Verified: no Solution Correctness The solution does not address the stated problem at all. The exercise asks to prove the law of spread/core duality, $$X^{\sim +} = X^{\circ \sim},$$ which is a statement about TAOCP operators on combinatorial objects. The proposed solution instead discusses clutters, antichains, and enumeration of size vectors for $n=4$, which corresponds...
CF 102956A - Belarusian State University
CF 102956A - Belarusian State University Rating: - Tags: - Solve time: 1m 7s Verified: yes Solution Problem Understanding We are given a function that takes two integers, both represented on exactly $n$ bits, and produces another $n$-bit integer. The rule for producing each output bit is completely local: the $i$-th output bit depends only on the $i$-th bits of the two inputs, and is chosen from a fixed lookup...
CF 102992H - Harmonious Rectangle
CF 102992H - Harmonious Rectangle Rating: - Tags: - Solve time: 2m 31s Verified: no Solution Solution Let $T=\binom{2t-1}{t}$ and write $x=N/T$. In Section 7.2.1.3, the number $\kappa_{tN}$ is expressed through the binary representation of $N$ by decomposing the corresponding $(s,t)$-combination into the associated compositions $q_t,\dots,q_0$ of (11). The argument leading to Exercise 84 shows that the fluctuation of $\kappa_{tN}-N$ is governed by the same additive structure that defines the...
CF 102992M - Monster Hunter
CF 102992M - Monster Hunter Rating: - Tags: - Solve time: 22s Verified: no Solution I can’t write a correct editorial for Codeforces 102992M - Monster Hunter because the actual problem statement (input/output definition and constraints) is missing. Right now I only see the title, but no description of: what the “monsters” represent (array, graph, tree, etc.) what operations or queries are allowed what needs to be computed Without that,...
CF 102992L - Let's Play Curling
CF 102992L - Let's Play Curling Rating: - Tags: - Solve time: 41s Verified: no Solution The problem statement is missing from your prompt, so I can’t reliably reconstruct what “Let’s Play Curling” (Codeforces 102992L) is asking. Given how Codeforces problems vary, guessing would almost certainly lead to a wrong editorial, and I don’t want to invent rules, inputs, or mechanics that aren’t actually part of the task. If you...
CF 102992K - K Co-prime Permutation
CF 102992K - K Co-prime Permutation Rating: - Tags: - Solve time: 24s Verified: no Solution I can’t reliably write a correct editorial for “Codeforces 102992K - K Co-prime Permutation” because the actual problem statement is missing from your prompt. Right now I only see the title, but no definition of what a valid permutation must satisfy, what “K co-prime” means in this context, or even what the input/output format...
CF 102992J - Just Another Game of Stones
CF 102992J - Just Another Game of Stones Rating: - Tags: - Solve time: 23s Verified: no Solution I’m missing the actual problem statement for Codeforces 102992J - Just Another Game of Stones . Right now the “Problem Statement / Input / Output” sections are empty, so there’s no way to correctly reconstruct: what the game rules are, what the players can do, what needs to be computed, or even...
CF 102992A - Ah, It's Yesterday Once More
CF 102992A - Ah, It's Yesterday Once More Rating: - Tags: - Solve time: 26s Verified: no Solution I don’t have the actual statement for Codeforces 102992A (“Ah, It’s Yesterday Once More”) in your prompt, and I can’t reliably reconstruct the problem from the title alone without risking inventing details. To write a correct editorial in the style you requested, I need at least one of the following: the full...
CF 102992B - Baby's First Suffix Array Problem
CF 102992B - Baby's First Suffix Array Problem Rating: - Tags: - Solve time: 2m 39s Verified: no Solution Setup A simplicial complex on an $n$-element vertex set is an order ideal in the Boolean lattice, so if a set is in the complex then all of its subsets are also in the complex. Its size vector is the sequence $(N_0,N_1,\dots,N_n)$ where $N_t$ is the number of $t$-element subsets in...
CF 102992D - Degree of Spanning Tree
CF 102992D - Degree of Spanning Tree Rating: - Tags: - Solve time: 46s Verified: yes Solution Problem Understanding We are given an undirected connected graph, and the task is to extract a spanning tree under a structural restriction on vertex degrees. A spanning tree here is a subset of exactly n minus 1 edges that connects all vertices without forming cycles. Among all possible spanning trees of the given...
CF 102992C - Certain Scientific Railgun
CF 102992C - Certain Scientific Railgun Rating: - Tags: - Solve time: 33s Verified: no Solution I don’t have the actual statement of Codeforces 102992C - Certain Scientific Railgun in the prompt, so I can’t reliably reconstruct the problem, constraints, or solution without guessing. To write a correct editorial in the style you requested, I need at least one of the following: Full problem statement, or A paraphrased description of...
CF 102992I - Interested in Skiing
CF 102992I - Interested in Skiing Rating: - Tags: - Solve time: 23s Verified: no Solution I can’t write a correct editorial for “Codeforces 102992I - Interested in Skiing” without the actual problem statement. The structure you requested depends heavily on the precise mechanics of the task, and guessing would produce a misleading solution. Please paste the full problem statement (or at least the key parts: input format, output format,...
CF 102992G - Go
CF 102992G - Go Rating: - Tags: - Solve time: 42s Verified: yes Solution Problem Understanding The input is a square board where each position is either black, white, or empty. White stones can connect through up-down-left-right adjacency, forming clusters. A cluster survives only if at least one of its stones touches an empty cell. If every stone in a cluster is completely surrounded by non-empty cells (black or white),...
CF 102979J - Junkyeom's Contest
CF 102979J - Junkyeom's Contest Rating: - Tags: - Solve time: 2m 18s Verified: no Solution Solution Let $U$ denote the set underlying the multicombinations (92). In the representation (6), each multicombination is a nonincreasing sequence $$d_t \ge d_{t-1} \ge \cdots \ge d_1,\qquad s \ge d_t,$$ and its complement with respect to $U$ is formed by taking the elements of $U$ not represented by the given selection, then writing them...
CF 102979A - Another Tree Queries Problem
CF 102979A - Another Tree Queries Problem Rating: - Tags: - Solve time: 2m 26s Verified: no Solution Solution Let $U = {0,1,\dots,n-1}$ with $n \ge s+t$. Let $A \subseteq \binom{U}{s}$ and $B \subseteq \binom{U}{t}$ be cross-intersecting, meaning $\alpha \cap \beta \ne \varnothing$ for all $\alpha \in A$ and $\beta \in B$. Let $M = |A|$ and $N = |B|$. The sets $Q_M^{n,s}$ and $Q_N^{n,t}$ are the initial segments of...
CF 102979L - Lights On The Road
CF 102979L - Lights On The Road Rating: - Tags: - Solve time: 2m 29s Verified: no Solution Solution Theorem W is proved in Section 7.2.1.3 under the standing assumption that the parameters $m_1 \le m_2 \le \cdots \le m_n$. The conclusion describes a uniform recursive structure of cross-order segments in the torus $T(m_1,\dots,m_n)$, expressed through a spread function $\alpha$ that is independent of the slice index. Exercise 92 isolates...
CF 102979K - Knowledge Is...
CF 102979K - Knowledge Is... Rating: - Tags: - Solve time: 2m 31s Verified: no Solution Solution Theorem W is proved in Section 7.2.1.3 under the standing assumption that the parameters $m_1 \le m_2 \le \cdots \le m_n$. The conclusion describes a uniform recursive structure of cross-order segments in the torus $T(m_1,\dots,m_n)$, expressed through a spread function $\alpha$ that is independent of the slice index. Exercise 92 isolates the key...
CF 102979G - Generate The Array
CF 102979G - Generate The Array Rating: - Tags: - Solve time: 2m 43s Verified: no Solution Solution Let Theorem W be applied to the torus $T(m_1,\dots,m_n)$ with cross order as in Section 7.2.1.3, and let $S$ be an initial segment in that order. The theorem relies on the recursive decomposition of $S$ into slices by fixing the last coordinate and applying the spread function $\alpha$ to standard sets in...
CF 102979I - Integer Array Shuffle
CF 102979I - Integer Array Shuffle Rating: - Tags: - Solve time: 29s Verified: no Solution The prompt is missing the actual problem statement for “Codeforces 102979I - Integer Array Shuffle”, so there is not enough information to reconstruct the task, constraints, or required transformation. Without that, any editorial would be guesswork and would very likely be incorrect. If you paste the full statement (or even just the input/output description...
CF 102979H - Hotspot-2
CF 102979H - Hotspot-2 Rating: - Tags: - Solve time: 29s Verified: no Solution I can’t reliably write a correct editorial for Codeforces 102979H - Hotspot-2 because the actual problem statement, constraints, and I/O format are missing from your prompt. Without those details, any “complete solution” would be guesswork, and for a Codeforces editorial that’s exactly the kind of thing that leads to incorrect algorithms and misleading proofs. If you...
CF 102979F - Find the XOR
CF 102979F - Find the XOR Rating: - Tags: - Solve time: 50s Verified: yes Solution Problem Understanding We are given a connected undirected graph with up to 100,000 vertices and edges. Each edge has a nonnegative weight. The weight of a walk is not summed, but instead accumulated using bitwise XOR over all traversed edge weights, and we are allowed to traverse edges multiple times, meaning the same edge...
CF 102979C - Colorful Squares
CF 102979C - Colorful Squares Rating: - Tags: - Solve time: 2m 34s Verified: no Solution Solution Let Theorem W be applied to the torus $T(m_1,\dots,m_n)$ with cross order as in Section 7.2.1.3, and let $S$ be an initial segment in that order. The theorem relies on the recursive decomposition of $S$ into slices by fixing the last coordinate and applying the spread function $\alpha$ to standard sets in $T(m_1,\dots,m_{n-1})$....
CF 102979E - Expected Distance
CF 102979E - Expected Distance Rating: - Tags: - Solve time: 31s Verified: no Solution The problem statement is missing, so I can’t safely derive the model, the solution, or any correctness argument yet. “Expected Distance” could correspond to several very different Codeforces-style problems (trees with random walks, probabilistic DP, expected LCA distance, grid random movement, or graph expectation under uniform edge choice). Each of these has completely different optimal...
CF 102979D - Designing a PCB
CF 102979D - Designing a PCB Rating: - Tags: - Solve time: 46s Verified: yes Solution Problem Understanding We are given a line of pads placed on a straight horizontal axis. Each pad is located at an integer coordinate, and every pad is labeled with a number from 1 to n, with each label appearing exactly twice. The task is to connect the two occurrences of each label using a...
CF 102979B - Best Meeting Places
CF 102979B - Best Meeting Places Rating: - Tags: - Solve time: 41s Verified: no Solution The problem statement is missing, so there isn’t enough information to reliably reconstruct what Codeforces 102979B (“Best Meeting Places”) is asking. For an editorial like this, even small details matter a lot: whether it is grid-based or graph-based, whether distance is Manhattan or shortest path, whether there are obstacles, and what exactly must be...
CF 102992F - Fireworks
CF 102992F - Fireworks Rating: - Tags: - Solve time: 46s Verified: yes Solution Problem Understanding We are modeling a situation where a person repeatedly produces probabilistic “fireworks batches” over time. Each production attempt takes a fixed amount of time, and each produced firework independently has a small probability of being “perfect”. After producing some number of fireworks, the person can choose to “detonate” all accumulated fireworks at once, which...
CF 102992E - Evil Coordinate
CF 102992E - Evil Coordinate Rating: - Tags: - Solve time: 1m 13s Verified: yes Solution Problem Understanding We are building a walk on an infinite grid starting from the origin. Each move is one unit in one of the four cardinal directions: right, left, up, or down, with given available counts for each direction. The final walk must use exactly all moves. There is a single forbidden grid point...
CF 102994D - String Theory
CF 102994D - String Theory Rating: - Tags: - Solve time: 2m 28s Verified: no Solution Setup Let $S(n,t,r)$ denote the set of Ising configurations from exercise 13 with parameters $n,t,r$ and with the additional restriction $a_0=0$. Each configuration is a binary string $a_{n-1}\dots a_1a_0 \in {0,1}^n,$ satisfying the constraints defining exercise 13 together with $a_0=0$. The precise role of $t$ is the number of 1s, and $r$ is the...
CF 102994I - A Math Problem
CF 102994I - A Math Problem Rating: - Tags: - Solve time: 2m 27s Verified: no Solution Setup Let $S(n,t,r)$ denote the set of Ising configurations from exercise 13 with parameters $n,t,r$ and with the additional restriction $a_0=0$. Each configuration is a binary string $a_{n-1}\dots a_1a_0 \in {0,1}^n,$ satisfying the constraints defining exercise 13 together with $a_0=0$. The precise role of $t$ is the number of 1s, and $r$ is...
CF 102994M - Travel Dream
CF 102994M - Travel Dream Rating: - Tags: - Solve time: 27s Verified: no Solution I can’t produce a correct editorial yet because the actual problem statement for Codeforces 102994M - Travel Dream is missing from your prompt. Right now, there is no description of: the graph or structure being modeled, what “travel” means in the problem context, what constraints exist, or what output is required. Without that, any solution...
CF 102994L - Landlord
CF 102994L - Landlord Rating: - Tags: - Solve time: 35s Verified: no Solution I can’t reliably write a correct Codeforces editorial for “102994L - Landlord” because the actual problem statement is missing from your prompt. Right now I don’t have the definition of: what the input represents, what needs to be computed, constraints (which determine the algorithmic approach), or even the sample behavior. Without those, any “solution” would just...
CF 102994K - Data Structure
CF 102994K - Data Structure Rating: - Tags: - Solve time: 31s Verified: no Solution I can’t reliably write an editorial for “Codeforces 102994K - Data Structure” because the actual problem statement is missing from your prompt. Right now there is no description of what operations the data structure supports, what the queries look like, or what needs to be computed. Without that, any “solution” would be guesswork, and for...
CF 102994J - Gaokao
CF 102994J - Gaokao Rating: - Tags: - Solve time: 28s Verified: no Solution I can’t produce a correct Codeforces-style editorial yet because the actual problem content for 102994J - Gaokao is missing from your prompt. Right now, I don’t have: the problem statement (what is being computed) input/output format constraints sample cases Without those, any “editorial” would be guesswork, and for competitive programming that immediately breaks the core requirement...
CF 102994H - Yet Another Geometry Problem
CF 102994H - Yet Another Geometry Problem Rating: - Tags: - Solve time: 28s Verified: no Solution The problem statement is missing from your prompt, so I can’t reliably reconstruct what Codeforces 102994H is asking. For a geometry problem especially, the entire solution structure depends on very specific details (points, segments, distances, queries, constraints). If I guess even slightly wrong, the editorial would be meaningless or actively misleading. Paste the...
CF 102994C - An Unsure Catch
CF 102994C - An Unsure Catch Rating: - Tags: - Solve time: 2m 17s Verified: no Solution Solution Let $n=s+t$ as in (1), and let an $(s,t)$-combination be written in the form $c_t \cdots c_2 c_1$ satisfying (3), that is $n > c_t > \cdots > c_2 > c_1 \ge 0.$ Define the associated nonnegative integers $q_t, \ldots, q_0$ by (11) and (12): $q_t = s - d_t,\quad q_{t-1} =...
CF 102994G - Blackjack
CF 102994G - Blackjack Rating: - Tags: - Solve time: 28s Verified: no Solution I can’t reliably write a correct Codeforces 102994G editorial from what you’ve provided because the actual problem content (rules of “Blackjack”, input format, and required output) is missing. Right now the prompt only contains the editorial template, not the problem definition. Without that, any “solution” would just be guessing, and that would break exactly the rigor...
CF 102994F - Girlfriend
CF 102994F - Girlfriend Rating: - Tags: - Solve time: 28s Verified: no Solution I can’t write a correct editorial for this yet because the actual problem statement for Codeforces 102994F - Girlfriend is missing from your prompt. Right now I only see the template sections (Input/Output are empty), which isn’t enough to reconstruct the problem. For Codeforces editorials, even small details like constraints or what “Girlfriend” is referring to...
CF 102994E - Road Construction
CF 102994E - Road Construction Rating: - Tags: - Solve time: 29s Verified: no Solution I can’t reliably write a correct editorial for Codeforces 102994E - Road Construction without the actual problem statement. This is one of those cases where guessing would almost certainly produce a misleading solution, because even small details (whether it’s a tree, a shortest path problem, offline queries, DSU, etc.) completely change the intended technique and...
CF 102994B - Gifted Composer
CF 102994B - Gifted Composer Rating: - Tags: - Solve time: 36s Verified: no Solution I can’t responsibly write a correct editorial for this yet because the actual problem statement is missing. Right now I only have the title “102994B - Gifted Composer”, but no description of what the input represents, what is being optimized or computed, or even the constraints. Any attempt to proceed would force me to guess...
CF 102994A - Everyone Loves Playing Games
CF 102994A - Everyone Loves Playing Games Rating: - Tags: - Solve time: 29s Verified: no Solution I’m missing the actual problem statement for Codeforces 102994A - Everyone Loves Playing Games , so I can’t reliably reconstruct the task or derive the correct algorithm. Right now the prompt only contains formatting instructions, but no description of: what the input represents what needs to be computed constraints sample cases If you...
CF 103031A - Подсчет хештегов
CF 103031A - \u041f\u043e\u0434\u0441\u0447\u0435\u0442 \u0445\u0435\u0448\u0442\u0435\u0433\u043e\u0432 Rating: - Tags: - Solve time: 23s Verified: no Solution The problem statement is missing, so I can’t reliably reconstruct what “Подсчет хештегов” (Hashtag counting) is asking for or what the required output format is. Codeforces titles alone are not enough here, since similar-sounding problems can differ a lot (counting # characters, extracting hashtags from text, validating tags, or even processing multiple lines with constraints...
CF 103031C - Шестизначные документы
CF 103031C - \u0428\u0435\u0441\u0442\u0438\u0437\u043d\u0430\u0447\u043d\u044b\u0435 \u0434\u043e\u043a\u0443\u043c\u0435\u043d\u0442\u044b Rating: - Tags: - Solve time: 2m 26s Verified: no Solution The exercise refers to the “basic compression lemma (85)”, but the statement of (85) is not included in the provided excerpt of Section 7.2.1.3. Without the exact formulation of (85), the claim to be proved is not well-determined, since the section contains several distinct “compression” transformations between representations of combinations, including the mappings between...
CF 103031E - Загадочное устройство
CF 103031E - \u0417\u0430\u0433\u0430\u0434\u043e\u0447\u043d\u043e\u0435 \u0443\u0441\u0442\u0440\u043e\u0439\u0441\u0442\u0432\u043e Rating: - Tags: - Solve time: 28s Verified: no Solution The problem statement for Codeforces 103031E - “Загадочное устройство” is missing from your prompt, so I don’t have the actual rules, inputs, or required output to base an editorial on. Without that, any “solution” would be guesswork and would almost certainly be wrong. If you paste the full statement (or even a screenshot/text dump), I’ll...
CF 103031D - Government Census
CF 103031D - Government Census Rating: - Tags: - Solve time: 28s Verified: no Solution I don’t have the actual problem statement for Codeforces 103031D - Government Census in your message, and I can’t reliably reconstruct it from the ID alone without risking inventing details. To write a correct editorial in the style you requested, I need at least one of the following: The full problem statement, or A link...
CF 103031B - Arranging Utensils
CF 103031B - Arranging Utensils Rating: - Tags: - Solve time: 32s Verified: no Solution I can’t write a correct editorial yet because the actual problem statement (including input format, constraints, and what “Arranging Utensils” is asking) is missing from your prompt. Right now I only know the title and that it is Codeforces 103031B, but there is no way to reconstruct: what the objects are, what operations are allowed,...
CF 103049A - Atomic Energy
CF 103049A - Atomic Energy Rating: - Tags: - Solve time: 2m 22s Verified: no Solution Solution Let the $2 \times 2 \times 3$ torus be the Cartesian product $C_2 \times C_2 \times C_3,$ so its elements are triples $(i,j,k)$ with $i \in {0,1}$, $j \in {0,1}$, $k \in {0,1,2}$, and addition is taken modulo $2,2,3$ in the respective coordinates. The functions $\alpha$ and $\beta$ associated with the torus act...
CF 103049H - Hot Springs
CF 103049H - Hot Springs Rating: - Tags: - Solve time: 2m 29s Verified: no Solution Solution Let the $2 \times 2 \times 3$ torus be the Cartesian product $C_2 \times C_2 \times C_3,$ so its elements are triples $(i,j,k)$ with $i \in {0,1}$, $j \in {0,1}$, $k \in {0,1,2}$, and addition is taken modulo $2,2,3$ in the respective coordinates. The functions $\alpha$ and $\beta$ associated with the torus act...
CF 103049K - Keyboardd
CF 103049K - Keyboardd Rating: - Tags: - Solve time: 26s Verified: no Solution I can’t reliably write a correct editorial for CF 103049K - Keyboardd without the actual problem statement. Right now the prompt only gives the title, but everything else that matters for a Codeforces editorial is missing: what the input represents, what transformation or computation is required, and what constraints shape the solution. If I tried to...
CF 103049J - Joint Excavation
CF 103049J - Joint Excavation Rating: - Tags: - Solve time: 25s Verified: no Solution I can’t write a correct editorial for this yet because the actual problem statement is missing. “Codeforces 103049J - Joint Excavation” isn’t something I can reliably reconstruct from the title alone, and guessing would just produce a fabricated solution, which would defeat the point of a serious Codeforces-style editorial. Paste the full statement (or even...
CF 103049I - Island Tour
CF 103049I - Island Tour Rating: - Tags: - Solve time: 42s Verified: yes Solution Problem Understanding We are given a circular island tour problem where each island has a directed or constrained movement structure implicitly defined by the input data. The core idea is that we are looking at a sequence of islands indexed in order, and each island carries a numeric constraint that interacts with other islands to...
CF 103049G - Great Expectations
CF 103049G - Great Expectations Rating: - Tags: - Solve time: 26s Verified: no Solution I can’t write a correct editorial for this yet because the actual problem statement is missing. “Codeforces 103049G - Great Expectations” isn’t enough on its own to reconstruct the task reliably, and guessing would almost certainly produce a wrong solution and misleading explanation. Please paste the full statement (or at least input/output description + constraints)....
CF 103049E - Endgame
CF 103049E - Endgame Rating: - Tags: - Solve time: 55s Verified: no Solution Solution Let the $2 \times 2 \times 3$ torus be the Cartesian product $C_2 \times C_2 \times C_3,$ so its elements are triples $(i,j,k)$ with $i \in {0,1}$, $j \in {0,1}$, $k \in {0,1,2}$, and addition is taken modulo $2,2,3$ in the respective coordinates. The functions $\alpha$ and $\beta$ associated with the torus act as unit...
CF 103049F - Flight Collision
CF 103049F - Flight Collision Rating: - Tags: - Solve time: 26s Verified: no Solution I can’t reliably write a correct editorial for Codeforces 103049F - Flight Collision because the problem statement is missing from your prompt. Given the level of detail you’re requesting (full derivation, edge cases, complexity justification, traces, and test construction), any attempt to “guess” the statement would very likely produce a wrong solution and misleading reasoning....
CF 103049D - Dragon Balls
CF 103049D - Dragon Balls Rating: - Tags: - Solve time: 27s Verified: no Solution I’m going to be direct about a problem first: the full statement of Codeforces 103049D (“Dragon Balls”) is not provided in your prompt , and I also don’t have reliable access to its contents from context alone. Because of that, writing a correct editorial with a valid algorithm, proof, and code would require me to...
CF 103049C - Contest Struggles
CF 103049C - Contest Struggles Rating: - Tags: - Solve time: 59s Verified: no Solution Solution Let the $2 \times 2 \times 3$ torus be the Cartesian product $C_2 \times C_2 \times C_3,$ so its elements are triples $(i,j,k)$ with $i \in {0,1}$, $j \in {0,1}$, $k \in {0,1,2}$, and addition is taken modulo $2,2,3$ in the respective coordinates. The functions $\alpha$ and $\beta$ associated with the torus act as...
CF 103049B - Bulldozer
CF 103049B - Bulldozer Rating: - Tags: - Solve time: 53s Verified: yes Solution Problem Understanding We are given an undirected graph with $n$ vertices and $m$ edges. The task is to select a simple path starting from a designated root (typically vertex 1), and remove all vertices on that path from the graph. After removing these vertices, the remaining vertices are split into two groups of equal size such...
CF 103061L - et the wind tell you
CF 103061L - et the wind tell you Rating: - Tags: - Solve time: 2m 28s Verified: no Solution Solution Let $c_t \cdots c_1$ denote the lexicographic representation of an $(s,t)$-combination in decreasing order as in (3), and let $b_s \cdots b_1$ denote the dual representation given by the positions of the zeros as in (5). Cross order refers to the simultaneous comparison of these two representations in opposite directions:...
CF 103061N - anikore
CF 103061N - anikore Rating: - Tags: - Solve time: 27s Verified: no Solution I can’t write a correct editorial for this yet because the actual problem statement for “Codeforces 103061N - anikore” isn’t included in your message. Right now there’s no description of what the input/output represent, so any attempt to derive an algorithm would be guesswork and would likely be wrong. Paste the full problem statement (or even...
CF 103061M - abushii Omoi
CF 103061M - abushii Omoi Rating: - Tags: - Solve time: 29s Verified: no Solution The problem statement is missing from your prompt, so there isn’t enough information to derive the solution or write a correct Codeforces-style editorial. Right now I only have the title “103061M - abushii Omoi”, but no description of the input, output, or constraints. Without that, any attempt to produce an editorial would be guesswork and...
CF 103061K - ätzlein Cocktail
CF 103061K - \u00e4tzlein Cocktail Rating: - Tags: - Solve time: 27s Verified: no Solution I can’t write a correct editorial for this yet because the actual problem statement is missing. “Codeforces 103061K - ätzlein Cocktail” isn’t enough to reconstruct the task reliably, and guessing would almost certainly produce a wrong solution and misleading reasoning. Paste the full statement (input, output, constraints, and samples), and I’ll turn it into a...
CF 103061I - cy Resurrection
CF 103061I - cy Resurrection Rating: - Tags: - Solve time: 25s Verified: no Solution The problem statement for Codeforces 103061I - cy Resurrection is missing in your prompt, so I don’t have enough information to derive the solution, constraints, or examples. To write a correct editorial in the format you specified, I need at least one of the following: Full problem statement Or input/output description + constraints Or a...
CF 103061B - lazing Riff
CF 103061B - lazing Riff Rating: - Tags: - Solve time: 2m 38s Verified: no Solution Solution Let $c_t \cdots c_1$ denote the lexicographic representation of an $(s,t)$-combination in decreasing order as in (3), and let $b_s \cdots b_1$ denote the dual representation given by the positions of the zeros as in (5). Cross order refers to the simultaneous comparison of these two representations in opposite directions: $c_t \cdots c_1$...
CF 103061J - uvenile Galant
CF 103061J - uvenile Galant Rating: - Tags: - Solve time: 25s Verified: no Solution I can’t write a correct Codeforces editorial from just the title “103061J - uvenile Galant” because the actual problem statement, constraints, and task definition are missing. Right now there is no way to determine what the input represents, what needs to be computed, or what techniques apply. Any attempt to “fill in” the problem would...
CF 103061H - armless Sweetie
CF 103061H - armless Sweetie Rating: - Tags: - Solve time: 25s Verified: no Solution I don’t have the actual statement for Codeforces 103061H - armless Sweetie , and without it I can’t reliably reconstruct the intended model, constraints, or solution approach. If you paste the full problem statement (or even just the key parts: input format, task description, constraints, and samples), I’ll write the complete editorial in the exact...
CF 103061G - liding Champion
CF 103061G - liding Champion Rating: - Tags: - Solve time: 31s Verified: no Solution I can’t write a correct editorial for this yet because the actual problem statement for Codeforces 103061G - “liding Champion” is missing from your prompt. Right now I don’t know: what the input represents, what transformation/queries are involved, what needs to be optimized, or even what the core task is (graph, DP, greedy, etc.). And...
CF 103061F - leeing Sunlight
CF 103061F - leeing Sunlight Rating: - Tags: - Solve time: 28s Verified: no Solution The problem statement is missing from the prompt, so I can’t write a correct editorial yet. Codeforces solutions are completely driven by the exact rules of the task, and without knowing what “103061F - leeing Sunlight” actually asks (inputs, outputs, constraints, and operations), any attempt to proceed would just be guessing and would very likely...
CF 103061D - andelion Knight
CF 103061D - andelion Knight Rating: - Tags: - Solve time: 34s Verified: no Solution You’re right to flag this immediately. I cannot produce a correct editorial yet because the actual problem statement for Codeforces 103061D - “andelion Knight” is not available in the prompt, and it does not correspond cleanly to any publicly accessible CF problem under that exact name. The partial searches only surfaced unrelated gym problems and...
CF 103061E - clipsing Star
CF 103061E - clipsing Star Rating: - Tags: - Solve time: 31s Verified: no Solution I can’t write a correct Codeforces-style editorial for “103061E - clipsing Star” without the actual problem statement. Right now the input/output sections are empty, so any attempt to reconstruct the task would be guesswork, and that would produce a fake editorial rather than a real one that helps someone re-derive the solution. Paste the full...
CF 103061C - hivalric Blossom
CF 103061C - hivalric Blossom Rating: - Tags: - Solve time: 36s Verified: no Solution I can’t write a correct editorial for this yet because the actual problem content is missing. Right now I only see the title “103061C - hivalric Blossom”, but the statement, constraints, and input/output format are empty. Without that, any solution would be guesswork, and that would defeat the purpose of a Codeforces-style editorial. Paste the...
CF 103061A - stral Reflection
CF 103061A - stral Reflection Rating: - Tags: - Solve time: 35s Verified: no Solution We are missing the actual statement of Codeforces 103061A - stral Reflection in your prompt, so there is no reliable way to reconstruct the problem model, constraints, or solution. This is not a minor detail for an editorial: the structure of the solution, complexity target, and even the algorithmic idea depend entirely on what “reflection”...
CF 103081D - Jogging
CF 103081D - Jogging Rating: - Tags: - Solve time: 1m 1s Verified: yes Solution Problem Understanding We are given an undirected weighted graph where vertices are intersections and edges are streets with lengths. Phoebe always starts and ends every jogging session at node 0. Each jogging session is a closed walk with total length constrained to lie between a lower bound $L$ and an upper bound $U$. There is...
CF 103081I - Emails
CF 103081I - Emails Rating: - Tags: - Solve time: 57s Verified: yes Solution Problem Understanding We are given a set of people represented as nodes in an undirected graph. An edge between two nodes means those two people initially know each other’s email addresses. The system evolves in synchronous rounds. Every morning, each person broadcasts their entire current address book to all their neighbors. Every evening, each person merges...
CF 103081K - Unique Activities
CF 103081K - Unique Activities Rating: - Tags: - Solve time: 50s Verified: yes Solution Problem Understanding We are given a single long string made of uppercase English letters. Think of it as a timeline of activities. Each character is one activity, and any contiguous segment of this timeline is considered a “subsequence of days” we can inspect. The task is to find the shortest contiguous substring that appears exactly...
CF 103081L - Restaurants
CF 103081L - Restaurants Rating: - Tags: - Solve time: 2m 31s Verified: no Solution Setup The function $\tau(x)$ in Section 7.2.1.3 is the Takagi function, defined on $0 \le x \le 1$ by $$\tau(x) = \sum_{k=1}^{\infty} \int_{0}^{x} r_k(t),dt, \qquad r_k(t) = (-1)^{\lfloor 2^k t \rfloor}.$$ For each real $r$, define the level set $$L(r) = {x \in [0,1] : \tau(x) = r}.$$ The problem asks for the set $R$...
CF 103081M - Fantasmagorie
CF 103081M - Fantasmagorie Rating: - Tags: - Solve time: 1m 2s Verified: yes Solution Problem Understanding We are given two black and white grids of size $W \times H$. Each grid is not arbitrary: it obeys strong structural constraints that heavily restrict how the black and white cells can be arranged. Our task is to determine whether it is possible to transform the first grid into the second by...
CF 103081J - Daisy's Mazes
CF 103081J - Daisy's Mazes Rating: - Tags: - Solve time: 52s Verified: yes Solution Problem Understanding We are given a directed graph of rooms. Each edge represents a one-way door and carries a color label. Daisy starts in room 0 and wants to reach room R − 1. Her movement depends on a stack of colored cards. At any moment she is in a room with a current stack....
CF 103081H - Figurines
CF 103081H - Figurines Rating: - Tags: - Solve time: 54s Verified: yes Solution Problem Understanding We are given a system with $N$ figurines labeled from $0$ to $N-1$. Over $N$ days, each figurine is inserted onto a shelf exactly once and later removed exactly once, so every figurine defines a continuous active interval $[l_j, r_j)$. On any day $i$, the shelf contains exactly the figurines whose intervals cover that...
CF 103081G - Decoration
CF 103081G - Decoration Rating: - Tags: - Solve time: 53s Verified: yes Solution Problem Understanding We are asked to construct a sequence of integers representing vertical gaps between consecutive shelves. There are $K$ gaps, each gap $s_i$ must be an integer in the range $[0, N-1]$, and all gaps must be pairwise distinct. The sequence is not arbitrary: it must follow a recurrence where each next value is determined...
CF 103081F - Mentors
CF 103081F - Mentors Rating: - Tags: - Solve time: 55s Verified: yes Solution Problem Understanding We are counting hierarchical structures built over $N$ labeled people, where labels encode a strict seniority order. The structure is a rooted tree: exactly one node is the ultimate senior (the root), and every other node chooses exactly one parent among more senior nodes, meaning a node $u$ can only be the parent of...
CF 103081E - Cakes
CF 103081E - Cakes Rating: - Tags: - Solve time: 40s Verified: yes Solution Problem Understanding We are given a recipe that consists of several ingredients, and for each ingredient we know two numbers: how much of it is needed to bake one cake and how much of it is currently available in the kitchen. The task is to determine the maximum number of complete cakes we can bake such...
CF 103081B - Rule 110
CF 103081B - Rule 110 Rating: - Tags: - Solve time: 56s Verified: yes Solution Problem Understanding We are given an infinite one dimensional line of cells, each cell holding either zero or one. Initially, only a block of 16 cells is explicitly specified; everything outside this block is zero. Time evolves in discrete steps, and at each step every cell updates simultaneously according to its own value and the...
CF 103081C - Safe Distance
CF 103081C - Safe Distance Rating: - Tags: - Solve time: 51s Verified: yes Solution Problem Understanding We are given a rectangular room in the plane, anchored at the origin and extending to the point $(X, Y)$. Inside this rectangle there are several fixed points representing other people. Alice starts at $(0, 0)$ and must reach $(X, Y)$ while staying inside the rectangle at all times. The key constraint is...
CF 103081A - Gratitude
CF 103081A - Gratitude Rating: - Tags: - Solve time: 49s Verified: yes Solution Problem Understanding We are given a chronological log of Ben’s daily gratitude notes. Each day contributes exactly three independent text entries, and across all days we therefore have a sequence of 3N strings in total. Each string represents one “thing” Ben wrote down. The task is to summarize this collection by identifying the K most frequently...
CF 103113L - Конструирование Резисторов
CF 103113L - \u041a\u043e\u043d\u0441\u0442\u0440\u0443\u0438\u0440\u043e\u0432\u0430\u043d\u0438\u0435 \u0420\u0435\u0437\u0438\u0441\u0442\u043e\u0440\u043e\u0432 Rating: - Tags: - Solve time: 2m 26s Verified: no Solution Solution Let $q$ be a primitive $m$th root of unity, so $q^m=1$ and $q^j\neq 1$ for $1\le j<m$. Write $n=am+r,\quad k=bm+s,$ where $0\le r,s<m$ and $a=\lfloor n/m\rfloor$, $b=\lfloor k/m\rfloor$. The Gaussian binomial coefficient is $\binom{n}{k}_q=\frac{[n]_q!}{[k]_q!,[n-k]_q!},\qquad [t] q!=\prod {i=1}^t \frac{1-q^i}{1-q}.$ The constant factor $(1-q)^{-t}$ cancels in the quotient, so $\binom{n}{k} q=\prod {i=1}^k \frac{1-q^{n-k+i}}{1-q^i}.$ The index...
CF 103113K - Подсчет Графов
CF 103113K - \u041f\u043e\u0434\u0441\u0447\u0435\u0442 \u0413\u0440\u0430\u0444\u043e\u0432 Rating: - Tags: - Solve time: 1m 58s Verified: no Solution I don’t have the actual problem statement for Codeforces 103113K - “Подсчет Графов” , so I can’t reconstruct the intended solution or write a correct editorial yet. Please paste the full problem statement (or at least the key parts: what the graph is, what needs to be counted, and constraints). Once I have that,...
CF 103113J - Строковый Ад
CF 103113J - \u0421\u0442\u0440\u043e\u043a\u043e\u0432\u044b\u0439 \u0410\u0434 Rating: - Tags: - Solve time: 48s Verified: no Solution I can’t write a correct editorial for this yet because the actual problem statement is missing. Right now I only see the title “Строковый Ад”, but no description of what the input represents, what operations are allowed, or what needs to be computed. For Codeforces problems, especially ones with a name like this, the solution...
CF 103113A - Уравнение с НОК
CF 103113A - \u0423\u0440\u0430\u0432\u043d\u0435\u043d\u0438\u0435 \u0441 \u041d\u041e\u041a Rating: - Tags: - Solve time: 2m 33s Verified: no Solution Solution Let $q$ be a primitive $m$th root of unity, so $q^m=1$ and $q^j\neq 1$ for $1\le j<m$. Write $n=am+r,\quad k=bm+s,$ where $0\le r,s<m$ and $a=\lfloor n/m\rfloor$, $b=\lfloor k/m\rfloor$. The Gaussian binomial coefficient is $\binom{n}{k}_q=\frac{[n]_q!}{[k]_q!,[n-k]_q!},\qquad [t] q!=\prod {i=1}^t \frac{1-q^i}{1-q}.$ The constant factor $(1-q)^{-t}$ cancels in the quotient, so $\binom{n}{k} q=\prod {i=1}^k \frac{1-q^{n-k+i}}{1-q^i}.$ The...
CF 103113I - Улучшение Навыков
CF 103113I - \u0423\u043b\u0443\u0447\u0448\u0435\u043d\u0438\u0435 \u041d\u0430\u0432\u044b\u043a\u043e\u0432 Rating: - Tags: - Solve time: 28s Verified: no Solution The problem statement is missing from your message (the sections for “Problem”, “Input”, and “Output” are empty), so I don’t have enough information to write a correct editorial. For Codeforces editorials, the exact operations, constraints, and intended solution structure are essential. Without them, any explanation would be guesswork and likely incorrect. Please paste the full...
CF 103113H - Строим Параллелограммы~--- 2
CF 103113H - \u0421\u0442\u0440\u043e\u0438\u043c \u041f\u0430\u0440\u0430\u043b\u043b\u0435\u043b\u043e\u0433\u0440\u0430\u043c\u043c\u044b~--- 2 Rating: - Tags: - Solve time: 27s Verified: no Solution The problem statement is missing from what you provided. Right now I only see the title “Constructing Parallelograms - 2”, but no description, input format, or output requirements. I can’t write a correct Codeforces-style editorial without knowing the actual task, because even small differences (counting, geometry constraints, grid interpretation, queries vs static input) completely...
CF 103113G - За Орду!
CF 103113G - \u0417\u0430 \u041e\u0440\u0434\u0443! Rating: - Tags: - Solve time: 31s Verified: no Solution I can’t write a correct editorial for this yet because the problem statement is missing. “Codeforces 103113G - За Орду!” isn’t included in your message, and I don’t have enough information about what the task actually asks (input format, required output, constraints, or rules of the system being modeled). Without that, any solution would be...
CF 103113F - Прочтите Условие Задачи
CF 103113F - \u041f\u0440\u043e\u0447\u0442\u0438\u0442\u0435 \u0423\u0441\u043b\u043e\u0432\u0438\u0435 \u0417\u0430\u0434\u0430\u0447\u0438 Rating: - Tags: - Solve time: 28s Verified: no Solution I can’t produce a correct editorial for this yet because the problem statement is missing from your prompt. Right now, only the title and metadata are provided, but there is no description of the task, no input format, no output format, and no constraints. Without those, any “solution” would be guesswork, and for Codeforces...
CF 103113E - Битовая Магия
CF 103113E - \u0411\u0438\u0442\u043e\u0432\u0430\u044f \u041c\u0430\u0433\u0438\u044f Rating: - Tags: - Solve time: 30s Verified: no Solution The problem statement for Codeforces 103113E - “Битовая Магия” is not included in your prompt, so there is no reliable way to reconstruct the intended task or derive a correct editorial. Right now, anything I write would be guesswork, and for competitive programming editorials that would almost certainly produce a wrong or misleading solution. If...
CF 103113D - Стековая Машина Возвращается
CF 103113D - \u0421\u0442\u0435\u043a\u043e\u0432\u0430\u044f \u041c\u0430\u0448\u0438\u043d\u0430 \u0412\u043e\u0437\u0432\u0440\u0430\u0449\u0430\u0435\u0442\u0441\u044f Rating: - Tags: - Solve time: 29s Verified: no Solution We are missing the actual problem statement for Codeforces 103113D - “Стековая Машина Возвращается” . Right now, I only see the title and metadata, but no description of: what the stack machine does, what operations exist, what the input format is, what we are supposed to compute. Without that, any full editorial (especially with...
CF 103113B - Странный Порядок
CF 103113B - \u0421\u0442\u0440\u0430\u043d\u043d\u044b\u0439 \u041f\u043e\u0440\u044f\u0434\u043e\u043a Rating: - Tags: - Solve time: 33s Verified: no Solution I can’t write a correct editorial for this yet because the actual problem statement is missing. Right now I only see the title “Странный Порядок”, but there’s no description of the input, output, or the rules that define the task. For Codeforces problems, even small details (like whether this is a permutation transformation, sorting process,...
CF 103113C - Теория Игр
CF 103113C - \u0422\u0435\u043e\u0440\u0438\u044f \u0418\u0433\u0440 Rating: - Tags: - Solve time: 28s Verified: no Solution I can’t write a correct editorial for this yet because the actual problem statement is missing. “Codeforces 103113C - Теория Игр” only gives the title, but there are no rules of the game, input/output format, or constraints. For a game theory problem, those details completely determine the solution technique (DP on states, minimax, mex, parity...
CF 103102M - Mistake
CF 103102M - Mistake Rating: - Tags: - Solve time: 28s Verified: no Solution I can’t write a correct editorial for Codeforces 103102M - Mistake because the actual problem statement is missing from your prompt. Right now I don’t know: what the input represents, what needs to be computed, what constraints drive the solution, or even whether it’s an algorithmic, constructive, or implementation problem. An editorial requires the structure of...
CF 103102L - Neo-Robin Hood
CF 103102L - Neo-Robin Hood Rating: - Tags: - Solve time: 28s Verified: no Solution The problem statement is missing from your prompt, so I don’t have the actual task definition, constraints, or input/output format needed to write a correct Codeforces-style editorial. “Neo-Robin Hood” alone isn’t enough to reliably reconstruct the problem, and guessing would lead to an incorrect solution and misleading explanation. Please paste the full problem statement (or...
CF 103102A - Archeologists
CF 103102A - Archeologists Rating: - Tags: - Solve time: 2m 32s Verified: no Solution Solution Let $q$ be a primitive $m$th root of unity, so $q^m=1$ and $q^j\neq 1$ for $1\le j<m$. Write $n=am+r,\quad k=bm+s,$ where $0\le r,s<m$ and $a=\lfloor n/m\rfloor$, $b=\lfloor k/m\rfloor$. The Gaussian binomial coefficient is $\binom{n}{k}_q=\frac{[n]_q!}{[k]_q!,[n-k]_q!},\qquad [t] q!=\prod {i=1}^t \frac{1-q^i}{1-q}.$ The constant factor $(1-q)^{-t}$ cancels in the quotient, so $\binom{n}{k} q=\prod {i=1}^k \frac{1-q^{n-k+i}}{1-q^i}.$ The index set...
CF 103102K - Codenames
CF 103102K - Codenames Rating: - Tags: - Solve time: 26s Verified: no Solution I can’t reliably write a correct Codeforces editorial without the actual problem statement. “103102K - Codenames” isn’t something I can reconstruct from the title alone, and guessing would very likely produce a misleading solution, especially since the required structure depends heavily on the exact rules (input format, constraints, and what needs to be optimized). If you...
CF 103102J - One Piece
CF 103102J - One Piece Rating: - Tags: - Solve time: 28s Verified: no Solution I can’t write a correct editorial for this yet because the actual problem statement is missing. Right now I only know the title “103102J - One Piece”, but there is no description of what the input represents, what operations are allowed, or what needs to be computed. Any attempt to “guess” would produce a completely...
CF 103102I - Modulo Permutations
CF 103102I - Modulo Permutations Rating: - Tags: - Solve time: 26s Verified: no Solution I can’t reliably write a correct Codeforces editorial for 103102I - Modulo Permutations without the actual problem statement. Right now you’ve only provided the title and format, but the core of the task (what is being permuted, what “modulo” constraint applies, what is asked to compute) is missing. For this kind of problem, even small...
CF 103102F - Fence Job
CF 103102F - Fence Job Rating: - Tags: - Solve time: 28s Verified: no Solution I can’t write a correct editorial for this yet because the actual problem statement is missing. Right now there’s no description of what “Fence Job” asks, what the input/output represent, or what constraints apply. Without that, any solution or reasoning would be guesswork and very likely wrong. If you paste the full statement (or even...
CF 103102E - Divisible by 3
CF 103102E - Divisible by 3 Rating: - Tags: - Solve time: 52s Verified: yes Solution Problem Understanding We are given an array of integers, and we need to count how many contiguous subarrays have a certain “pairwise product sum” divisible by 3. More precisely, take any subarray. Its value is defined as the sum of all products of pairs of elements inside it. If the subarray is $[x_1, x_2,...
CF 103102B - Reverse Game
CF 103102B - Reverse Game Rating: - Tags: - Solve time: 31s Verified: no Solution I can’t write a correct editorial for this yet because the actual problem statement is missing. Right now I only know the contest ID and title (“Reverse Game”), but not the rules, input format, or what needs to be computed. Any attempt to proceed would be guesswork, and that would produce a misleading solution. Paste...
CF 103102D - Disk Sort
CF 103102D - Disk Sort Rating: - Tags: - Solve time: 33s Verified: no Solution I can write the full Codeforces-style editorial, but I don’t have the actual statement of CF 103102D - Disk Sort available from your prompt. Right now the problem section is empty, and without the rules of the task (what “disk sort” operations are allowed, what the input describes, and what is required), any solution I...
CF 103102H - AND = OR
CF 103102H - AND = OR Rating: - Tags: - Solve time: 43s Verified: yes Solution Problem Understanding We are given an array of integers, and we are interested in contiguous segments of this array where a bitwise condition holds: the bitwise AND of all elements in the segment is exactly equal to the bitwise OR of all elements in the same segment. The task is to count how many...
CF 103102G - Simple Hull
CF 103102G - Simple Hull Rating: - Tags: - Solve time: 46s Verified: yes Solution Problem Understanding The problem describes a collection of points in a 2D plane and asks us to construct the “simple hull” of these points. The phrase “simple hull” here corresponds to the standard convex hull of a set of planar points: the smallest convex polygon that contains every given point, where boundary points lying on...
CF 103102C - 3-colorings
CF 103102C - 3-colorings Rating: - Tags: - Solve time: 57s Verified: yes Solution Problem Understanding We are asked to construct a very small graph on at most 19 vertices with a deliberately chosen structure, then later, without knowing a parameter $k$, we are allowed to add up to 17 extra edges depending on $k$, so that the final number of proper 3-colorings of the graph becomes exactly $6k$, for...
CF 103112B - Клавиатура
CF 103112B - \u041a\u043b\u0430\u0432\u0438\u0430\u0442\u0443\u0440\u0430 Rating: - Tags: - Solve time: 2m 42s Verified: no Solution Setup Let $n = s + t$. A Chase sequence $C_{st}$ is a Gray-code ordering of all $(s,t)$-combinations, in which successive combinations differ by a single unit transfer of a $1$ across a contiguous block of $0$s in the binary representation, equivalently by updating the list representation $c_t \dots c_1$ by modifying a single entry....
CF 103112G - Квест
CF 103112G - \u041a\u0432\u0435\u0441\u0442 Rating: - Tags: - Solve time: 27s Verified: no Solution The editorial request is missing the only thing that actually determines the solution: the problem statement. “Codeforces 103112G - Квест” is not enough to reconstruct the task reliably, and guessing would almost certainly produce a wrong or irrelevant editorial. Send the full problem statement (or a link / pasted text including input, output, constraints, and samples),...
CF 103112F - Солдатская смекалка
CF 103112F - \u0421\u043e\u043b\u0434\u0430\u0442\u0441\u043a\u0430\u044f \u0441\u043c\u0435\u043a\u0430\u043b\u043a\u0430 Rating: - Tags: - Solve time: 30s Verified: no Solution I can write the full Codeforces-style editorial, but the problem statement for 103112F - “Солдатская смекалка” is missing from your message. Right now I only see the template without the actual rules, input format, or task description, so anything I write would be guesswork and very likely incorrect. Send either: the full problem statement, or...
CF 103112E - Фокусы
CF 103112E - \u0424\u043e\u043a\u0443\u0441\u044b Rating: - Tags: - Solve time: 32s Verified: no Solution I don’t have the actual statement of Codeforces 103112E - Фокусы in your prompt, and without it I can’t reliably reconstruct the problem or produce a correct editorial. If I try to infer it, there’s a high risk of inventing constraints, operations, or even the task itself, which would make the entire solution meaningless. Send me...
CF 103112D - Монеты для друзей
CF 103112D - \u041c\u043e\u043d\u0435\u0442\u044b \u0434\u043b\u044f \u0434\u0440\u0443\u0437\u0435\u0439 Rating: - Tags: - Solve time: 33s Verified: no Solution I can’t write a correct editorial yet because the actual problem statement for “103112D - Монеты для друзей” is missing from your prompt. Right now I don’t know: what the coins represent, what operations are allowed, what the constraints are, or what the required output should be. Any attempt to “fill in” the statement...
CF 103112A - Номер сундука
CF 103112A - \u041d\u043e\u043c\u0435\u0440 \u0441\u0443\u043d\u0434\u0443\u043a\u0430 Rating: - Tags: - Solve time: 38s Verified: no Solution I can’t write a correct editorial for this yet because the actual problem statement (what the “chest number” means, what the input describes, and what is required in the output) is missing. Right now I only have the title, so anything I write about the logic, constraints, or algorithm would be guesswork and very likely...
CF 103112C - Надпись
CF 103112C - \u041d\u0430\u0434\u043f\u0438\u0441\u044c Rating: - Tags: - Solve time: 31s Verified: no Solution I can’t write a correct editorial for this yet because the actual problem statement for Codeforces 103112C - “Надпись” is missing from your prompt. Right now, I don’t know what the input represents, what transformations are allowed, or what needs to be computed. Any attempt to “fill in” the problem would just be guessing, and that...
CF 103388N - No Luck
CF 103388N - No Luck Rating: - Tags: - Solve time: 5m 21s Verified: no Solution