brain

I don’t have the actual statement of Codeforces 102942D - XOR Game in your prompt, and that problem ID doesn’t correspond to a standard indexed CF problem I can reliably reconstruct.

We are given a sequence of integers and we are allowed to perform a simple operation that modifies elements so that, after applying it any number of times, we want every element in the sequence to become odd.

I can’t write a correct editorial for Codeforces 102942C - Team without the actual problem statement. That contest ID isn’t something I can reliably reconstruct from memory alone, and guessing would very likely produce a wrong solution and misleading reasoning.

Algorithm H generates all integer partitions $a1 ge cdots ge am ge 1$ of $n$ by maintaining a weakly decreasing sequence whose entries are positive and whose sum is always $n$.

We are given a weighted undirected graph where vertices represent locations on an island and edges represent paths between them. The hero starts at node 1 and wants to reach node N. Traveling along an edge takes one minute and consumes energy equal to the edge weight.

We are given a stream of customers who arrive over time at a single counter. Each customer has an arrival time and a tip value. If a customer is accepted, they join a FIFO line and are served one by one, with each service taking exactly the same fixed amount of time.

Let the $2times 2times 3$ torus be the Cartesian product $$T = mathbb{Z}2 times mathbb{Z}2 times mathbb{Z}3,$$ so each element is a triple $(x,y,z)$ with $x,y in {0,1}$ and $z in {0,1,2}$, with arithmetic taken modulo $2,2,3$ respectively. This gives $12$ vertices.

We are given a single array of positive weights along a line, representing how much delivery load each rabbit family contributes. Each day, we are given a contiguous segment of this array, and we must split that segment into exactly $k$ contiguous groups.

We are given a small collection of positive integers. From this collection, we consider every possible non-empty subset and compute the greatest common divisor of the numbers inside that subset. A subset is considered “valid” if this gcd equals exactly 1.

We are given a directed graph representing a city road system, where each road can only be used in one direction and every road has unit cost in the sense that we will eventually count how many roads we decide to keep.

We are given a rectangular grid of size up to 100 by 100. Each cell represents a seat and is already painted either green, blue, or left neutral. Green and blue are fixed, while neutral seats can be freely assigned either green or blue.

We are given a rectangular grid representing a store floor plan. Each cell contains a direction character that acts like a deterministic instruction: if a customer stands on that cell, they move one step north, south, east, or west according to the arrow.

We are given a simple daily log of customer arrivals to a bubble tea shop. Each day has a number of customers, and every time the total number of customers reaches a multiple of a fixed value k, that customer receives a free drink.

Let the $2times 2times 3$ torus be the Cartesian product $$T = mathbb{Z}2 times mathbb{Z}2 times mathbb{Z}3,$$ so each element is a triple $(x,y,z)$ with $x,y in {0,1}$ and $z in {0,1,2}$, with arithmetic taken modulo $2,2,3$ respectively. This gives $12$ vertices.

We are given six sensors in 3D space, each tied to a specific cube face color. In a valid configuration, these sensors must each touch one face of a solid cube of side length d. The cube itself is not axis-aligned, so we are free to rotate and translate it arbitrarily in space.

We are working with a very small square grid, at most eight by eight, where each cell either contains a fish or is empty. Alongside this grid there is a special token, the sea urchin, which occupies exactly one cell and moves every day to a neighboring cell that shares an edge.

Let the $2times 2times 3$ torus be the Cartesian product $$T = mathbb{Z}2 times mathbb{Z}2 times mathbb{Z}3,$$ so each element is a triple $(x,y,z)$ with $x,y in {0,1}$ and $z in {0,1,2}$, with arithmetic taken modulo $2,2,3$ respectively. This gives $12$ vertices.

We are asked to distribute a total of k fish into n fish tanks, where each tank must contain a positive integer number of fish.

We are given two hidden permutations, both containing the numbers from 1 to n exactly once. One permutation is a cyclic rotation of the other, but we do not know either of them and we also do not know the rotation amount k.

We are given a grid of size $n times m$ where each cell is either 0 or 1. From this grid, we consider every possible subrectangle aligned with the grid lines.

We are given a list of integers representing water volumes in several fish tanks. For each tank, we need to compute a value based on two parts of the number: the number itself and the sum of its digits.

Let $n,m ge 1$. The goal is to generate all partitions of $n$ into at most $m$ parts, meaning sequences $a1 ge a2 ge cdots ge ak ge 1,quad k le m,quad a1+cdots+ak=n.

I don’t have the statement for Codeforces 102947K - Call of the Wild available in the prompt, and I can’t reliably reconstruct it from the title alone without risking inventing details.

I can’t reliably write a correct editorial for Codeforces 102947J - Camping in the Wild without the actual problem statement. Right now the input/output specification and the core task are missing, so any solution I produce would be guesswork and very likely wrong.

I can’t reliably write a correct Codeforces editorial for “102947I - Food Allocation II” without the actual problem statement.

I’m missing the actual problem statement for Codeforces 102947H - Jungle Escape, and without it I can’t reliably reconstruct the correct model, constraints, or solution approach.

I don’t have the actual statement of Codeforces 102947G - Food Rations available in your prompt, and the rest of the sections depend entirely on the precise rules of the problem (what operations are allowed, what “rations” means, and what is being optimized or checked).

I’m missing the actual problem statement for Codeforces 102947F - Hopping Between Lily Pads, so I can’t reliably reconstruct the mechanics, constraints, or required solution.

We are given a square matrix of size $n times n$, where each entry describes how much value a particular survivor contributes if assigned to a particular food type.

I don’t have the actual problem statement for Codeforces 102947C - White Fang in your prompt, so I can’t reliably reconstruct the intended solution or write a correct editorial without guessing.

Let the 2 × 2 × 3 torus be the Cartesian product of directed cycles $C2 times C2 times C3$, with vertex set $V = {(i,j,k) mid i in {0,1}, j in {0,1}, k in {0,1,2}}.

I can’t write a correct editorial without the actual problem statement. Right now the “Problem Statement / Input / Output” sections are empty, and Codeforces problems with the same title can vary significantly in mechanics (greedy, DP, simulation, etc.).

I can’t reliably write a correct editorial for this yet because the actual problem statement is missing. “Codeforces 102948H - Jungle Escape” by itself doesn’t tell me what the graph, grid, or constraints are, so any attempt to derive an algorithm would be guesswork and…

I can’t reliably reconstruct Codeforces 102948D - Firewood from the title alone, and it does not appear in standard indexed problem listings in a way that exposes the statement.

The problem statement for Codeforces 102948F - Hopping Between Lily Pads is missing from your prompt, so I can’t reconstruct the mechanics (graph structure, allowed moves, constraints, or what is being optimized). An editorial depends heavily on those details.

I can’t produce a correct editorial for this yet because the actual problem statement for Codeforces 102948E - Food Allocation I is missing from your prompt.

The problem statement is missing from your prompt, so I don’t have enough information to write a correct editorial.

I can write this editorial, but I’m missing the only thing that actually determines the solution: the problem statement.

Let the 2 × 2 × 3 torus be the Cartesian product of directed cycles $C2 times C2 times C3$, with vertex set $V = {(i,j,k) mid i in {0,1}, j in {0,1}, k in {0,1,2}}.

We start with an array that is conceptually extremely large, indexed from 0 up to $10^9 - 1$, but initially every position contains zero. Instead of storing this array explicitly, we are given two types of operations that modify and query ranges.

I can’t reliably write a correct editorial for Codeforces 102951E - KRUZNICE because the actual problem statement is missing from your prompt. “kruznice” suggests something about circles, but that’s not enough to reconstruct the task, constraints, or required output.

We are given two sequences that contain the same elements in different orders, typically two permutations of length $n$.

I can’t write a correct editorial for this yet because the actual problem statement is missing. “Codeforces 102951B - Studying Algorithms” alone doesn’t contain enough information to reconstruct the task, constraints, or required technique, and guessing would very likely…

I don’t have the actual statement for Codeforces 1029532 - Array Condensation, and without it I’d be forced to guess the operations, constraints, and goal, which would make the editorial unreliable.

Let $t=r+s$.

Let the 2 × 2 × 3 torus be the Cartesian product of directed cycles $C2 times C2 times C3$, with vertex set $V = {(i,j,k) mid i in {0,1}, j in {0,1}, k in {0,1,2}}.

I can’t write a correct Codeforces editorial for this yet because the actual problem content is missing. Right now I only see the title, time/memory limits, and empty sections for the statement, input, and output.

I’m missing the actual problem statement for “Codeforces 1029538 - Number Placement” in your prompt, and I can’t reliably reconstruct it from the ID alone.

I can’t reliably write an editorial for “Codeforces 1029537 - Maximum Plus Sign” because the actual problem statement (grid definition, input format, constraints, and required output) is missing from your prompt.

I can’t reliably write a correct Codeforces editorial without the actual problem statement. “1029536 - Favorite Product” doesn’t correspond to a standard public Codeforces problem I can reconstruct, and the solution details (what the input represents, what is being…

We are given a group of students and a log of encounters between pairs of them. Some students are initially infected, and whenever an infected student has been recorded as meeting another student, the infection spreads through that contact relationship.

Let the 2 × 2 × 3 torus be the Cartesian product of directed cycles $C2 times C2 times C3$, with vertex set $V = {(i,j,k) mid i in {0,1}, j in {0,1}, k in {0,1,2}}.

We are given a long strip of lowercase letters representing available stickers. Each complete banner must spell the fixed word “coderams” exactly once per banner, using the stickers in order of availability but not necessarily contiguous positions in the original string.

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.

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.

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.

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.

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.

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.

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.

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.

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…

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.

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.

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 $a1 dots ai$ is exactly equal to the smallest value seen in…

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.

We are given a function that takes two integers, both represented on exactly $n$ bits, and produces another $n$-bit integer.

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.

We are given a sequence of numbers, and for every position we want to find a “nearest smaller value” that appears before it.

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.

We are given a sequence of numbers and a target value, and the task is to determine whether there exist four distinct positions in the sequence such that the values at those positions add up exactly to the target.

We are given a sequence of numbers and a target value. The task is to determine whether there exist three distinct elements in the sequence whose sum equals the target, and if so, return their positions in the original array.

Each task has two properties: how long it takes to finish and a deadline that is used to evaluate how “late” you are when you complete it. You must execute all tasks sequentially starting from time zero, choosing any order you want.

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.

We are given a collection of independent factory machines, each of which can repeatedly produce identical items. The i-th machine produces one item every fixed amount of time, so if it runs for a total time T, it contributes roughly T divided by its processing time, rounded…

You’re right to stop me here before I start inventing details. The problem statement is missing from the prompt you provided, so an editorial cannot be written correctly yet.

We are given a collection of intervals on the number line, each interval representing a segment with a left endpoint and a right endpoint. For every interval, we need to understand its position relative to all other intervals in terms of nesting.

We are simulating a circular elimination process over a line of people labeled from 1 to n. A step size k is fixed.

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.

I can’t write a correct Codeforces editorial without the actual problem statement. “Traffic Lights” (Codeforces 102961O) isn’t provided here, and there are multiple well-known variants of problems with that name (online insertion of lights on a street segment, queries…

I can write the full Codeforces-style editorial, but I’m missing the actual problem statement for Codeforces 102961N - Towers.

We are given a permutation of the integers from 1 to $n$, arranged in some order. Alongside this, we receive a sequence of operations, where each operation swaps two positions in the permutation.

I don’t have the actual statement of Codeforces 102961M - Playlist in your prompt. Without the problem details (input format, constraints, and required output), I can’t produce a correct editorial or solution.

We are given a sequence of integers representing a permutation-like arrangement of distinct numbers. The task is to determine how many “rounds” it takes to process all numbers in increasing order, where each round consists of scanning the sequence from left to right and…

We are given a collection of positive integers that can be interpreted as coin values. Each value can be used at most once, and by selecting some subset of these coins we can form different total sums.

We are given a sequence of integers, and we need to find the maximum possible sum of a contiguous segment of that sequence. A contiguous segment means we pick a starting position and an ending position, and take all elements in between without skipping any.

We are given a list of integers and a target value. The task is to determine whether there exist two distinct elements in the list whose sum equals the target. If such a pair exists, we must output their positions (typically 1-indexed).

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.

I don’t have the actual statement for Codeforces 102961F - Movie Festival, so I can’t reliably reconstruct the correct model, constraints, or solution. For an editorial, guessing would just produce a misleading write-up.

The task revolves around a marketplace of fixed-priced concert tickets and a sequence of buyers arriving one after another. Each ticket has a price, and each buyer has a maximum amount they are willing to pay.

We are given a timeline of customer visits to a restaurant, where each customer appears at some moment and leaves at some later moment. Each customer contributes a continuous time interval during which they are present inside the restaurant.

We are given a line of people, each with a weight, and a Ferris wheel where each cabin can hold at most two people as long as their combined weight does not exceed a fixed limit.

The task is about taking a sequence of integers and determining how many different values appear in it. You are given a list of numbers, and the output is a single integer representing the size of the set formed by these numbers, meaning duplicates are ignored and only unique…

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.

We are working with a graph that has a special structure. There is a distinguished node labeled 0, and every other node from 1 to n is directly connected to it by an edge whose weight is given initially.

We are given a collection of puzzle pieces, each piece behaving like a rigid segment with a fixed length and two labeled endpoints. Each endpoint is one of three types: flat, convex, or concave. Pieces cannot be flipped, so left and right sides are fixed.

We are given a one-dimensional parking strip divided into unit cells. Some cells are already blocked, others are free. Over time, a sequence of vehicles arrives. Each vehicle is either a motorcycle that occupies one free cell or a car that occupies two adjacent free cells.

Let a partition of $n$ have Ferrers diagram with Durfee square of size $k$, meaning that the largest square subdiagram is $k\times k$.

We are given a line of robots, each permanently associated with one of three actions: rock, paper, or scissors. The only operation we can perform is to repeatedly choose two adjacent robots and make them “fight”, after which one of them is removed according to the usual RPS…

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.