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CF 272C - Dima and Staircase

The problem presents a staircase of n steps, where each step has a certain height given in a non-decreasing array a. Dima throws boxes vertically onto the staircase. Each box has a width w and a height h, and it covers the first w stairs.

codeforcescompetitive-programmingdata-structuresimplementation
Kvant Math Problem 1304

I cannot write a solution to Kvant problem M1304 from the information currently available.

kvantmathematicsolympiad
Kvant Math Problem 1303

I can begin writing a full solution, but I need the **text of problem M1303** from Kvant before proceeding.

kvantmathematicsolympiad
Kvant Math Problem 1302

I cannot write a solution to Kvant problem M1302 because the actual problem statement is not available in your message.

kvantmathematicsolympiad
CF 272E - Dima and Horses

We are asked to partition a group of horses into two parties in such a way that no horse has more than one enemy in the same party. The input lists the number of horses n and a number of enemy pairs m, followed by m pairs of horse indices indicating mutual enmity.

codeforcescompetitive-programmingcombinatoricsconstructive-algorithmsgraphs
Kvant Math Problem 1301

I cannot write a solution to Kvant problem M1301 from the information provided, because the problem statement itself is missing.

kvantmathematicsolympiad
CF 272D - Dima and Two Sequences

We are given two lists of points. The first list fixes points on distinct vertical positions, so the i-th point is tied to index i but has an x-coordinate given by a[i].

codeforcescompetitive-programmingcombinatoricsmathsortings
CF 272B - Dima and Sequence

We are given a sequence of positive integers and a function that maps each integer to a non-negative value. The function is defined recursively: it sends zero to zero, it ignores factors of two, and every time we encounter an odd number we effectively contribute one unit and…

codeforcescompetitive-programmingimplementationmath
CF 271C - Secret

We are asked to distribute n sequentially numbered words among k Keepers such that each Keeper receives a non-empty subset of words, the subsets are pairwise disjoint, their union covers all words, and no subset forms an arithmetic progression.

codeforcescompetitive-programmingconstructive-algorithmsimplementation
CF 271A - Beautiful Year

We are given a four-digit year and we want to move forward in time until we reach the next year whose decimal representation does not reuse any digit.

codeforcescompetitive-programmingbrute-force
CF 271E - Three Horses

We start with a set of “cards”, each card is a pair of integers $(a, b)$ with $a < b$. From one initial card $(x, y)$, we can repeatedly apply three transformation rules that behave like operations on this pair.

codeforcescompetitive-programmingconstructive-algorithmsmathnumber-theory
CF 271D - Good Substrings

We are given a string made of lowercase English letters. Each letter is labeled as either good or bad using a separate 26-character binary mask. We are also given an integer k, which limits how many bad letters we are allowed to tolerate inside a substring.

codeforcescompetitive-programmingdata-structuresstrings
CF 271B - Prime Matrix

We are given a grid of positive integers. From this grid, we are allowed to repeatedly choose any single cell and increment its value by one. Each increment costs one move.

codeforcescompetitive-programmingbinary-searchbrute-forcemathnumber-theory
CF 269A - Magical Boxes

We are asked to determine the size of the smallest magical box that can contain a given set of smaller boxes. Each box has a side length that is a power of two, specifically 2^k for some integer k.

codeforcescompetitive-programminggreedymath
Kvant Math Problem 1300

I do not yet have the full textual statement of Kvant problem M1300.

kvantmathematicsolympiad
CF 269B - Greenhouse Effect

We are given a sequence of plants positioned along a line, each plant belonging to one of m species. The greenhouse is long but narrow, so each plant has a unique position along this line, and all positions are strictly increasing.

codeforcescompetitive-programmingdp
Kvant Math Problem 1299

Consider small values of $n$ to gain insight.

kvantmathematicsolympiad
CF 269E - String Theory

I can't reliably produce a correct editorial and accepted reference solution for Codeforces 269E from the problem statement alone.

codeforcescompetitive-programminggeometrymathstrings
CF 269D - Maximum Waterfall

We have a set of horizontal panels attached to a wall. Water starts from the artificial "top panel" at height t and must eventually reach the artificial "bottom panel" at height 0.

codeforcescompetitive-programmingdata-structuresdpgraphssortings
Kvant Math Problem 1298

I can prepare the solution, but I need the text of the Kvant M1298 problem to proceed.

kvantmathematicsolympiad
CF 269C - Flawed Flow

We are given an undirected connected graph with n vertices and m edges, where each edge has a flow value already assigned. The vertices are numbered from 1 to n, with vertex 1 as the source and vertex n as the sink.

codeforcescompetitive-programmingconstructive-algorithmsflowsgraphsgreedy
CF 268A - Games

We are given the uniform colors of all teams in a football championship. Each team has a home color and an away color. Every ordered pair of distinct teams plays exactly one match, with one team acting as the host and the other as the guest.

codeforcescompetitive-programmingbrute-force
Kvant Math Problem 1297

The equations for $\alpha$ and $\beta$ are cubic but not immediately factorable in integer roots.

kvantmathematicsolympiad
CF 268C - Beautiful Sets of Points

We are given all lattice points inside a rectangle, meaning every point $(x,y)$ with integer coordinates such that $0 le x le n$, $0 le y le m$, and $(0,0)$ is excluded.

codeforcescompetitive-programmingconstructive-algorithmsimplementation
CF 268E - Playlist

Each song has two attributes. Its length is l, and independently Manao likes it with probability p. When a song is played for the first time, one of two things happens. If he likes it, the song is added to a collection of remembered songs.

codeforcescompetitive-programmingmathprobabilitiessortings
Kvant Math Problem 1296

Consider the operation described in the problem: a polygon is cut along a line segment into two pieces, one piece is flipped, and the pieces are reattached along the cut line.

kvantmathematicsolympiad
CF 268D - Wall Bars

The problem asks us to count how many ways we can place horizontal bars on a vertical pole of height n, such that a child starting on the ground can climb to the top section of the pole, moving only along bars in the same direction and not exceeding a vertical distance of h…

codeforcescompetitive-programmingdp
CF 268B - Buttons

There is a hidden order of n buttons. A button only stays pressed if it is the next correct button in that order. If at any point we press a wrong button, every previously pressed button pops back out and we must start building the sequence again from the beginning.

codeforcescompetitive-programmingimplementationmath
Kvant Math Problem 1295

Consider small examples of the problem to understand the dynamics.

kvantmathematicsolympiad
CF 217B - Blackboard Fibonacci

We start with two numbers on the blackboard, (0, 1). Operation T replaces the top number by the sum of both numbers. Operation B does the same for the bottom number. After exactly n operations, we look at the number written by the last operation.

codeforcescompetitive-programmingbrute-forcemath
Kvant Math Problem 1294

Consider a smaller cube, for instance $2\times2\times2$ or $4\times4\times4$, with a checkerboard coloring.

kvantmathematicsolympiad
CF 217C - Formurosa

The formula describes a Boolean function built from constants 0 and 1, placeholders ?, and the operators AND, OR, and XOR. Each ? corresponds to a leaf of the plant. During an experiment, we choose which colony is placed on each leaf.

codeforcescompetitive-programmingdivide-and-conquerdpexpression-parsing
CF 217D - Bitonix' Patrol

The problem is essentially about circular modular arithmetic and subset sums. We have a circular orbit of n stations, each separated by m miles. Captain Bitonix has a set of fuel tanks, each with a certain capacity.

codeforcescompetitive-programmingbitmasksbrute-forcecombinatoricsdfs-and-similarmath
CF 217A - Ice Skating

We are given a set of snow drifts on a 2D grid with integer coordinates. Bajtek can move only in straight lines along the x or y axis, sliding from one drift until he hits another.

codeforcescompetitive-programmingbrute-forcedfs-and-similardsugraphs
CF 195B - After Training

We are asked to simulate the process of distributing numbered footballs into a row of baskets according to a specific order. Each new ball must go into the basket that currently contains the fewest balls.

codeforcescompetitive-programmingdata-structuresimplementationmath
Kvant Math Problem 1293

Consider an angle with vertex $A$ and two rays forming the sides.

kvantmathematicsolympiad
CF 195A - Let's Watch Football

The video lasts for c seconds. Watching one second of video consumes a units of data, while the internet connection downloads only b units per second. Since a b, starting immediately is impossible because data would be consumed faster than it arrives.

codeforcescompetitive-programmingbinary-searchbrute-forcemath
Kvant Math Problem 1292

Begin by considering the simplest nontrivial cases.

kvantmathematicsolympiad
Kvant Math Problem 1291

The problem statement is missing.

kvantmathematicsolympiad
CF 195E - Building Forest

We are asked to construct a special kind of directed forest where each vertex has at most one outgoing edge, and each edge carries a weight. Vertices are added one by one. When adding a vertex, we are optionally given a set of pairs consisting of an existing vertex and a number.

codeforcescompetitive-programmingdata-structuresdsugraphs
CF 195D - Analyzing Polyline

We are asked to analyze the polyline formed by summing several linear functions. Each function is of the form $yi(x) = ki cdot The input consists of $n$ lines, each providing the slope $ki$ for the positive $x$-side and a constant $bi$.

codeforcescompetitive-programminggeometrymathsortings
CF 195C - Try and Catch

We are given the source code of a tiny language that contains only three kinds of statements: try, catch(type, message), and exactly one throw(type). Each try is paired with a later catch, forming a try-catch block.

codeforcescompetitive-programmingexpression-parsingimplementation
CF 188G - Array Sorting

The task is to sort a list of integers in non-descending order. You are given the size of the list, n, and then n integers, each on a separate line, with values ranging from 1 to 100.

codeforcescompetitive-programming*specialimplementation
CF 188A - Hexagonal Numbers

We are asked to calculate the n-th hexagonal number. Hexagonal numbers represent a figurate number pattern where each number counts the total tiles forming a hexagon with successive layers. The formula for the n-th hexagonal number is given by $Hn = 2n^2 - n$.

codeforcescompetitive-programming*special
Kvant Math Problem 1290

The folding is performed only along the grid lines.

kvantmathematicsolympiad
Kvant Math Problem 1289

Let

kvantmathematicsolympiad
Kvant Math Problem 1288

The number is

kvantmathematicsolympiad
Kvant Math Problem 1287

Consider a parallelogram $ABCD$ with $AC > BD$ and a point $M$ on $AC$ such that $BCDM$ is cyclic.

kvantmathematicsolympiad
Kvant Math Problem 1286

Consider a small case to understand the structure.

kvantmathematicsolympiad
Kvant Math Problem 1285

Let a permutation of the deck be written as a sequence.

kvantmathematicsolympiad
Kvant Math Problem 1284

Consider an isosceles triangle $ACB$ with base $AB$ and vertex $C$.

kvantmathematicsolympiad
Kvant Math Problem 1283

The figure shows three allowed tile types.

kvantmathematicsolympiad
Kvant Math Problem 1282

Consider two trapezoids $ABCD$ and $A'B'C'D'$ such that the legs of each are equal to the bases of the other.

kvantmathematicsolympiad
CF 188H - Stack

The input is a string that describes operations on a stack. Each digit means "push this number onto the stack". Each + or means "take the top two values from the stack, apply the operation, and push the result back".

codeforcescompetitive-programming*specialexpression-parsingimplementation
CF 188C - LCM

We are given two positive integers and need to compute their least common multiple. The least common multiple, usually abbreviated as LCM, is the smallest positive integer that is divisible by both numbers without leaving a remainder.

codeforcescompetitive-programming*specialimplementationmath
Kvant Math Problem 1281

Consider two positive numbers $x$ and $y$ such that $xy > x + y$.

kvantmathematicsolympiad
Kvant Math Problem 1280

The decimal expansion of $\dfrac1{3^{100}}$ is purely periodic after a finite preperiod, because $3^{100}$ is coprime to $10$.

kvantmathematicsolympiad
Kvant Math Problem 1278

For $n=2$, the conditions give $x_2=-x_1$ and $2x_1^2=1$, hence $x_1x_2=-\frac12\le-\frac12=-\frac1n$.

kvantmathematicsolympiad
Kvant Math Problem 1277

Begin by testing small values of $n$.

kvantmathematicsolympiad
Kvant Math Problem 1276

Consider a fixed chord $MN$ of a circle and a variable diameter $AB$ that does not intersect $MN$.

kvantmathematicsolympiad
Kvant Math Problem 1275

Let

kvantmathematicsolympiad
Kvant Math Problem 1274

Denote

kvantmathematicsolympiad
Kvant Math Problem 1273

Before I can write the full solution, I need the full text of Kvant problem M1273 in order to proceed.

kvantmathematicsolympiad
Kvant Math Problem 1272

Begin with small values of $n$ to gain intuition.

kvantmathematicsolympiad
Kvant Math Problem 1271

Let the semicircle have radius $R$ and center $O$.

kvantmathematicsolympiad
Kvant Math Problem 1269

Let $a=AB$ and $c=AC$.

kvantmathematicsolympiad
Kvant Math Problem 1268

Consider triangle $ABC$ with an interior point $X$, and let $AX$, $BX$, $CX$ intersect the opposite sides at $A_1$, $B_1$, $C_1$ respectively.

kvantmathematicsolympiad
Kvant Math Problem 1267

Consider small values of $n$ to understand the behavior of the remainders $r_k$.

kvantmathematicsolympiad
Kvant Math Problem 1266

Consider small cases with integer points in a bounded region.

kvantmathematicsolympiad
Kvant Math Problem 1264

Consider a small portion of the infinite grid and attempt to construct a $2\times 2$ black square using only $3\times 3$ and $4\times 4$ flip operations.

kvantmathematicsolympiad
Kvant Math Problem 1263

Let the outer circle have center $O$ and radius $R$.

kvantmathematicsolympiad
Kvant Math Problem 1262

Let the side lengths be $a,b,c$.

kvantmathematicsolympiad
Kvant Math Problem 1261

Consider small examples with three colors and a uniform degree graph.

kvantmathematicsolympiad
Kvant Math Problem 1260

Examine small integers $n>1$ to see when $\frac{2^n+1}{n^2}$ is an integer.

kvantmathematicsolympiad
Kvant Math Problem 1259

Before proceeding, I need the full textual statement of Kvant problem M1259.

kvantmathematicsolympiad
Kvant Math Problem 1258

I see that you have provided the framework for solving Kvant problem M1258, but I do not yet have the text of the problem itself.

kvantmathematicsolympiad
Kvant Math Problem 1257

Before I start the full solution, I need the precise statement of Kvant problem M1257.

kvantmathematicsolympiad
Kvant Math Problem 1256

The circles are equal and tangent to each other.

kvantmathematicsolympiad
Kvant Math Problem 1255

I cannot write a rigorous solution to Kvant problem M1255 because the actual problem statement is not present in your message.

kvantmathematicsolympiad
Kvant Math Problem 1254

Before I write the full solution, I need the precise text of Kvant problem M1254.

kvantmathematicsolympiad
Kvant Math Problem 1253

A complete solution cannot be written because the problem statement is not available.

kvantmathematicsolympiad
Kvant Math Problem 1252

I cannot write a solution to Kvant problem M1252 because the actual problem statement is not present.

kvantmathematicsolympiad
Kvant Math Problem 1251

I notice that the problem statement for Kvant M1251 is not fully given in text form.

kvantmathematicsolympiad
Kvant Math Problem 1249

The road system is a tournament: for every pair of cities exactly one directed edge joins them.

kvantmathematicsolympiad
Kvant Math Problem 1248

For the first statement, it is natural to place the original segment on the real line as $[0,L]$.

kvantmathematicsolympiad
Kvant Math Problem 1247

Consider tiling the plane with squares of side lengths $1, 2, 4, 8, \dots$ under the two constraints: using each size at most ten times or using each size once.

kvantmathematicsolympiad
Kvant Math Problem 1246

Let the arithmetic progression be

kvantmathematicsolympiad
Kvant Math Problem 1245

Begin by considering small cases, such as $n = 2$ or $n = 3$, to develop intuition.

kvantmathematicsolympiad
Kvant Math Problem 1244

Label the 30 senators as vertices of a graph where edges represent friendship.

kvantmathematicsolympiad
Kvant Math Problem 1243

For the quadratic game, the first player provides three numbers $a$, $b$, $c$, and the second player can assign them arbitrarily to the coefficients of $x^2$, $x$, and the constant term.

kvantmathematicsolympiad
Kvant Math Problem 1242

Consider a small regular polygon, for instance a regular hexagon or octagon, to visualize the positions of points $K$ on $AB$ and $N$ on $BC$.

kvantmathematicsolympiad
Kvant Math Problem 1241

For a small instance with piles $1,2,3$, one move cannot remove all stones, because the three pile sizes are different.

kvantmathematicsolympiad
Kvant Math Problem 1240

A broken line from $A$ to $C$ of length $2n$ along the grid lines must consist of exactly $n$ horizontal and $n$ vertical unit steps.

kvantmathematicsolympiad
Kvant Math Problem 1239

The problem statement is not actually present in your message.

kvantmathematicsolympiad
Kvant Math Problem 1238

I can follow your requested six-section format and rigorous style.

kvantmathematicsolympiad
Kvant Math Problem 1237

I cannot write a solution to Kvant problem M1237 because the actual problem statement is not included in your message, and I do not have access to the graphical version from the published issue.

kvantmathematicsolympiad
Kvant Math Problem 1236

I see the framework and instructions, but I do not yet have the actual text of Kvant problem M1236.

kvantmathematicsolympiad
Kvant Math Problem 1235

I cannot write a solution to Kvant problem M1235 because the actual problem statement is not included in your message.

kvantmathematicsolympiad
Kvant Math Problem 1234

I can start preparing the full Kvant-style solution, but I need the actual problem statement for M1234 to proceed.

kvantmathematicsolympiad
CF 267C - Berland Traffic

We are given a directed system of roads connecting a small number of intersections. Each road has a capacity, meaning there is a maximum amount of traffic that can be assigned to it in total, regardless of direction.

codeforcescompetitive-programmingmathmatrices