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41230 notes

CF 103457F - Размещение симбиотов

I can’t reliably write a correct editorial for Codeforces 103457F - “Размещение симбиотов” without the actual problem statement.

codeforcescompetitive-programming
CF 103457A - Тщательное планирование

The problem statement section is empty, so there isn’t enough information to derive the algorithm, constraints, or even what the task is asking for. For a Codeforces editorial, the actual input/output definition is essential.

codeforcescompetitive-programming
CF 103457D - Спрятать заложницу

I can’t write a correct editorial for this yet because the actual problem content for Codeforces 103457D - “Спрятать заложницу” is missing from your prompt.

codeforcescompetitive-programming
CF 103457C - В поисках Венома

The problem statement for “Codeforces 103457C - В поисках Венома” is missing from your message, so I don’t have the actual task definition, input/output format, or constraints.

codeforcescompetitive-programming
CF 103457B - Активная подготовка к битве

I can’t produce a correct editorial yet because the actual problem statement is missing from your prompt. Right now I only see: - Problem title: “Активная подготовка к битве” - No description of the input, output, or rules Without that, any…

codeforcescompetitive-programming
CF 103458J - Magical Clock

The problem statement section is empty, so there’s not enough information to derive an algorithm, constraints, or even what the input/output represent.

codeforcescompetitive-programming
CF 103458I - Палиндромная шифровка

I don’t have the actual problem statement for Codeforces 103458I - “Палиндромная шифровка” in the prompt you provided, and I can’t reliably reconstruct it from the title alone without risking inventing details.

codeforcescompetitive-programming
CF 103458H - Компонентная химия

I need to be honest first: the full statement of Codeforces 103458H - Компонентная химия is not reliably available in a clean form from standard sources, and the snippets that exist are partial and inconsistent across archives.

codeforcescompetitive-programming
CF 103458G - Взрывоопасная лестница

I can’t reliably write a correct editorial for this yet because the actual problem statement is missing. Right now I only have the title “Взрывоопасная лестница” (“Explosive staircase”), but no description of what the stairs do, what constitutes a…

codeforcescompetitive-programming
CF 103458F - Поезда в Зауне

I’m missing the actual problem statement for Codeforces 103458F - “Поезда в Зауне”, so I can’t safely reconstruct the solution or write a correct editorial yet.

codeforcescompetitive-programming
CF 103458E - Джинкс и лагерь миротворцев

I’m missing the actual problem content for “103458E - Джинкс и лагерь миротворцев” (the statement, constraints, and I/O format are empty in your message).

codeforcescompetitive-programming
CF 103458B - Производство Мерцания

I can’t reliably write a correct editorial for this without the actual problem statement. Right now the prompt only includes the title “103458B - Производство Мерцания”, but no description, input/output format, or constraints.

codeforcescompetitive-programming
CF 103458D - Тренировки миротворцев

We are missing the actual statement of Codeforces 103458D in the prompt you provided. The problem name “Тренировки миротворцев” (“Peacekeepers’ training”) exists, but the task description (what is given, what must be computed, and constraints) is…

codeforcescompetitive-programming
TAOCP 7.2.1.3 Exercise 2

Let $r_s,\dots,r_0$ satisfy t = r_s + \cdots + r_1 + r_0,\qquad 0 \le r_j \le m_j \quad (s \ge j \ge 0).

taocpmathematicsalgorithmsvolume-4medium
CF 103458C - Опасные игры

The process being modeled is a turn-based elimination game played on a circular gun cylinder with a fixed number of chambers. Some chambers contain bullets and others are empty.

codeforcescompetitive-programming
CF 103458A - Цепная реакция

I can’t reliably reconstruct the problem from “Codeforces 103458A - Цепная реакция” with the information available here, and the web results are not giving a consistent statement for that exact index.

codeforcescompetitive-programming
CF 103462H - Hsueh- And Treasure

We are standing on an infinite grid starting at the origin. Each test gives a target coordinate, and we must construct a walk that eventually reaches that point. The movement rule is unusual: time is split into phases.

codeforcescompetitive-programming
CF 103462L - Little H And Reboot

We are given a set of rectangular boxes placed somewhere on a large 2D plane. Each box is described by four corner points in counterclockwise order, so every obstacle is a convex quadrilateral with arbitrary orientation, not necessarily axis-aligned.

codeforcescompetitive-programming
CF 103462J - Jew Sorting

We are given an array whose length is exactly a power of two, specifically $2^k$, where $k$ can be as large as 20. Each operation takes the current array and throws away exactly one half of it, either the left half or the right half, and keeps the other half unchanged.

codeforcescompetitive-programming
CF 103462K - K-Clearing II

We are given an integer array and a special value $k$. The process is dynamic: as long as the array still contains at least one element equal to $k$, we repeatedly apply an operation that decreases every positive element of the array by one.

codeforcescompetitive-programming
CF 103462G - Guess Strings

We are interacting with a hidden string of length at most 100. The string uses exactly two distinct lowercase letters, but we are not told which ones. Our only way to learn about it is by asking whether a chosen pattern appears as a contiguous substring of the hidden string.

codeforcescompetitive-programming
CF 103462I - Iaom and Chicken feet

We are given a tree, meaning a connected acyclic graph on $n$ nodes with $n-1$ edges. The task is to count how many distinct subgraphs of a specific shape appear inside this tree.

codeforcescompetitive-programming
CF 103462F - Fill the Binary String

We are given a binary string where some positions are already fixed as 0 or 1, while others are unknown and marked with ?. We are allowed to replace each ? with either 0 or 1, producing a fully binary string.

codeforcescompetitive-programming
CF 103462E - Eaom and Longzhu

We are given a directed or undirected weighted graph of rooms connected by portals. The traveler starts in room 1 and wants to reach room n. Every time he enters a room, he collects exactly one item called a “longzhu”, and each longzhu has one of 7 types.

codeforcescompetitive-programming
CF 103462D - Double Pleasure

We are given a large integer range $[A, B]$, and for each query we must count how many integers inside this range satisfy a special divisibility condition. For a number $x$, we compute the product of its decimal digits. Call this value $P(x)$.

codeforcescompetitive-programming
CF 103462B - Baom and Fibonacci

We are asked to evaluate a double summation over Fibonacci numbers indexed by pairs of integers up to a very large bound.

codeforcescompetitive-programming
CF 103462C - Circle Minimal

We are given a connected undirected graph with exactly one more edge than a tree would have. That means the graph contains exactly one cycle somewhere inside it, while the remaining edges form tree-like attachments to that cycle.

codeforcescompetitive-programming
CF 103462A - Array Permutation

We are building an array of length $n$ using a process that grows it in chunks. Initially the array is empty. At any moment, if the current length is $m$, we choose a number $x$ between $1$ and $n-m$. After choosing $x$, we append the sequence $1, 2, 3, dots, x$ to the array.

codeforcescompetitive-programming
TAOCP 7.2.1.3 Exercise 1

Let $r_s,\dots,r_0$ satisfy t = r_s + \cdots + r_1 + r_0,\qquad 0 \le r_j \le m_j \quad (s \ge j \ge 0).

taocpmathematicsalgorithmsvolume-4math-medium
CF 103463M - Rikka with Random Graph

We are given a directed graph on up to one hundred thousand vertices, but the edges are not explicitly listed in the input. Instead, the graph is generated internally using a deterministic pseudo-random generator seeded by two integers.

codeforcescompetitive-programming
CF 103463K - LTS buy wine

A row of wine bottles is placed from left to right, each bottle having a fixed intrinsic value. Every day exactly one bottle is removed from either the left end or the right end of the current row.

codeforcescompetitive-programming
CF 103463L - Line problem

We are given two line segments in the plane for each test case. Each segment is defined by two endpoints with integer coordinates. The task is to compute how much of these two segments overlaps along their geometry, but only when the overlap forms a segment of positive length.

codeforcescompetitive-programming
CF 103463J - Hsueh- owns large quantities of apples

We are modeling a deterministic transfer process that starts with a single pile of apples and moves through a line of m children. The first child receives all n apples.

codeforcescompetitive-programming
CF 103463H - Hsueh- and keyboard

We are given an initial text buffer whose only relevant property is its length, call it x. From this starting state, we want to transform the buffer so that its length becomes exactly n using a set of keyboard operations.

codeforcescompetitive-programming
CF 103463I - LTS and rectangular area union

We are given a sequence of axis-aligned rectangles that all sit on the x-axis, meaning every rectangle has its bottom edge on $y = 0$. Each rectangle $i$ spans an interval $[Li, Ri]$ on the x-axis and has height $Hi$.

codeforcescompetitive-programming
CF 103463G - LTS owns large quantities of apples

We are simulating a deterministic transfer process of apples across a line of $m$ children. The process starts with an initial number $n$, which is given to the first child.

codeforcescompetitive-programming
CF 103463F - Hsueh- Love Matrix

We are given a rectangular grid with $n$ rows and $m$ columns. Each cell $(i, j)$ contains the value $i cdot j$. So row 1 is $1, 2, dots, m$, row 2 is $2, 4, dots, 2m$, and so on.

codeforcescompetitive-programming
CF 103463E - The King Of Sum Xor

We are given two 64-bit non-negative integers, a target sum $S$ and a target xor value $X$. We are allowed to construct an array of non-negative integers, possibly empty, such that the sum of its elements equals $S$ and the bitwise xor of its elements equals $X$.

codeforcescompetitive-programming
CF 103463C - Hoogle Machine Translation

We are given a collection of words, and we must produce their corresponding translations in the same order. The only way to obtain translations is through an interactive machine. The machine behaves in two consistent ways. If we query a single word, it returns its translation.

codeforcescompetitive-programming
CF 103463D - Dup4 and pebble pile

We are given a contiguous range of integers from $a$ to $b$, and initially each number stands alone as its own pile. We are allowed to merge two piles if we can find a number in each pile that shares a prime factor $t$ with $t ge p$.

codeforcescompetitive-programming
CF 103463A - A simple problem

We are given a set of digits from 0 to n, and we are asked to consider all possible permutations of these digits. Each permutation is interpreted as a number by concatenating the digits in order.

codeforcescompetitive-programming
CF 103463B - Hsueh- play balls

We have a box initially containing two types of indistinguishable balls, n white and m black. We repeatedly remove one ball uniformly at random until the box becomes empty.

codeforcescompetitive-programming
CF 103464B - Palindromic Dates

An additive alphametic in the sense of Section 7.2.1.2 assigns distinct decimal digits to distinct letters so that a formal arithmetic identity between words becomes a true equality of base-10 integers.

codeforcescompetitive-programming
CF 103464D - A Task With Queries

I don’t have the actual statement of Codeforces 103464D “A Task With Queries” in the prompt, so I can’t reliably reconstruct the operations, constraints, or intended solution path.

codeforcescompetitive-programming
CF 103464A - Stegosauruses

We are given a collection of stegosauruses, each associated with a single integer value representing the number of spikes it has.

codeforcescompetitive-programming
CF 103464C - Protected String

I can’t reliably write a correct editorial for “Codeforces 103464C - Protected String” because the actual problem statement is missing.

codeforcescompetitive-programming
TAOCP 7.2.1.2 Exercise 99

Let a 4-note chord be a 4-combination $c_4c_3c_2c_1$ with $n > c_4 > c_3 > c_2 > c_1 \ge 0.$ A single “adjacent-key move” replaces exactly one $c_j$ by $c_j \pm 1$ while preserving strict inequalities...

taocpmathematicsalgorithmsvolume-4math-hard
CF 103466J - Spy

Let $S{s,t}$ denote the set of all bitstrings $a{n-1}cdots a0$ with $n=s+t$ containing exactly $t$ ones, and let $C{s,t}$ denote the corresponding set of index lists $ctcdots c1$ with $nctcdotsc1ge 0$, ordered lexicographically as in (3).

codeforcescompetitive-programming
CF 103466K - Triangle

We are given a fixed triangle in the plane, defined by three vertices with integer coordinates. Along with this triangle, we are given a point $P$, which is supposed to lie on the boundary of the triangle.

codeforcescompetitive-programming
CF 103466I - Space Station

We are given a collection of space stations indexed from 0 to n. Each station has an integer energy value, and station 0 is our starting point.

codeforcescompetitive-programming
CF 103466H - Prince and Princess

We are given a closed world consisting of people distributed across rooms, with no empty rooms. Every person belongs to exactly one of three behavioral types: supporters of the marriage, opponents of the marriage, and neutral participants.

codeforcescompetitive-programming
CF 103466B - Chessboard

Let $S{s,t}$ denote the set of all bitstrings $a{n-1}cdots a0$ with $n=s+t$ containing exactly $t$ ones, and let $C{s,t}$ denote the corresponding set of index lists $ctcdots c1$ with $nctcdotsc1ge 0$, ordered lexicographically as in (3).

codeforcescompetitive-programming
CF 103466G - Poker Game

This is a simulated poker tournament where five fixed-strategy players repeatedly participate in a series of independent rounds.

codeforcescompetitive-programming
CF 103466E - Observation

We are given several test cases. In each test case, there is a range of integer distances from L to R. For each integer distance d in this range, the problem defines a value f(d), which counts how many integer-coordinate points in 3D space lie exactly at Euclidean distance d…

codeforcescompetitive-programming
CF 103466F - Paper Grading

We maintain a dynamic list of strings, indexed from 1 to n, which can be reordered by swap operations. Alongside this evolving list, we receive queries asking about a segment of indices [l, r] and a query string q together with a threshold k.

codeforcescompetitive-programming
CF 103466D - Holes

We are given an $n times n$ grid where a subset of cells are marked as absorbing “holes”. A token starts from a fixed cell $(r, c)$ that is guaranteed not to be a hole.

codeforcescompetitive-programming
CF 103466A - A Hard Problem

We are given a set of integers from 1 up to n. The task is to determine the smallest number k such that no matter how we choose any subset of size k from this range, we are guaranteed to find two distinct numbers u and v inside that subset where one divides the other.

codeforcescompetitive-programming
CF 103466C - Digital Path

We are given an integer grid where each cell contains a value, and we need to count certain special paths formed by moving through adjacent cells in the grid.

codeforcescompetitive-programming
CF 103469L - Little LCS

We are given two strings, each of length $2n+1$, over the alphabet ${A,B,C}$ plus wildcard characters ?. Each ? can be replaced independently by any of the three letters.

codeforcescompetitive-programming
CF 103469M - Math

Codeforces 103469M: Math

codeforcescompetitive-programming
CF 103469K - K-onstruction

We are asked to construct a short integer array such that the number of its subsets whose sum is exactly zero equals a given value K.

codeforcescompetitive-programming
CF 103469J - Joke

We are given a fixed permutation $p$ of size $n$, and a partially specified permutation $q$ of the same size. Some positions in $q$ are known, others are zero and must be filled so that the final sequence becomes a valid permutation of $1$ to $n$.

codeforcescompetitive-programming
CF 103469I - Intellectual Implementation

We are given a collection of axis-aligned rectangles in the plane. Each rectangle is defined by a closed x-interval and a closed y-interval, so it represents a solid filled region.

codeforcescompetitive-programming
CF 103469G - Glory Graph

We are given a complete graph where every pair of vertices is connected by an edge colored either blue or yellow. The input is essentially an $n times n$ symmetric matrix encoded as characters, where each off-diagonal entry tells us the color of an edge.

codeforcescompetitive-programming
TAOCP 7.2.1.2 Exercise 98

Let a 4-note chord be a 4-combination $c_4c_3c_2c_1$ with $n > c_4 > c_3 > c_2 > c_1 \ge 0.$ A single “adjacent-key move” replaces exactly one $c_j$ by $c_j \pm 1$ while preserving strict inequalities...

taocpmathematicsalgorithmsvolume-4hm-medium
CF 103469H - Hamiltonian

Codeforces 103469H: Hamiltonian

codeforcescompetitive-programming
CF 103469F - Fancy Formulas

We are given a pair of values $(a, b)$ over a finite field modulo a prime $p$. Each query asks for the minimum number of operations needed to transform a starting pair $(ai, bi)$ into a target pair $(ci, di)$, where each operation applies one of two deterministic transformations.

codeforcescompetitive-programming
CF 103469E - Eulerian?

We are given a hidden simple undirected connected graph on $n$ vertices. We cannot see its edges directly. Instead, we can query any subset of vertices and receive the number of edges whose both endpoints lie entirely inside that subset. The task is not to reconstruct the graph.

codeforcescompetitive-programming
CF 103469D - Deleting

We start with a sequence of labels from 1 to n, arranged in increasing order. The only allowed operation is to pick two adjacent elements in the current sequence, remove them both, and pay a cost that depends on the original labels of the two removed elements.

codeforcescompetitive-programming
CF 103469B - Bruteforce

We are given an array of integers that changes over time through point updates. After every update, we need to compute a special “weight” of the array. To compute this weight, we first sort the array in non-decreasing order.

codeforcescompetitive-programming
CF 103469C - Crab's Cannon

We are given a target string length l and a set of distinct positions a1, a2, ..., an, each in the range [1, l]. These positions are known to be exactly the palindromic prefix lengths of some unknown string, except that some of them may have been deleted.

codeforcescompetitive-programming
CF 103469A - AND

We are given a set of integers that is known to come from some hidden array. The process that produced this set is as follows: take every contiguous subarray of the hidden array, compute the bitwise AND of that subarray, and collect all distinct results.

codeforcescompetitive-programming
CF 103470M - Windblume Festival

I don’t have the actual problem statement for Codeforces 103470M - Windblume Festival, so I can’t reliably reconstruct the task or derive a correct solution.

codeforcescompetitive-programming
CF 103470L - Secret of Tianqiu Valley

I can’t reliably write a correct editorial for Codeforces 103470L - Secret of Tianqiu Valley because the actual problem statement is missing from your prompt.

codeforcescompetitive-programming
CF 103470J - Xingqiu's Joke

I can’t write a correct editorial for this yet because the problem statement is missing. Right now, all we have is the title “Xingqiu’s Joke”, but no description of the input, output, constraints, or rules.

codeforcescompetitive-programming
CF 103470K - Ancient Magic Circle in Teyvat

The problem statement is missing from your prompt (both the description and input/output sections are empty), so I can’t reconstruct the intended solution or write a correct editorial.

codeforcescompetitive-programming
CF 103470G - Paimon's Tree

We are given a tree with $n+1$ vertices and an ordering of $n$ weights. The process starts by choosing any vertex as a root and marking it black.

codeforcescompetitive-programming
CF 103470H - Crystalfly

The problem statement is missing from the prompt, so there isn’t enough information to derive the solution, constraints, or even the underlying task (graph, DP, combinatorics, etc.).

codeforcescompetitive-programming
CF 103470I - Cloud Retainer's Game

The problem statement is missing, so there isn’t enough information to write a correct editorial. “Cloud Retainer’s Game” could correspond to multiple unknown tasks, and without the actual rules, constraints, or input/output definition, any solution would be guesswork…

codeforcescompetitive-programming
CF 103470E - Paimon Segment Tree

I can’t write a correct editorial for this yet because the actual problem content (operations, constraints, and required queries) is missing from your prompt.

codeforcescompetitive-programming
CF 103470F - Paimon Polygon

The problem statement for Codeforces 103470F - Paimon Polygon is missing from your prompt, so I don’t have the actual rules, inputs, or required computation to build a correct editorial.

codeforcescompetitive-programming
CF 103470D - Paimon Sorting

We are given an array of integers, and we repeatedly apply a very unusual sorting procedure. The procedure does not compare neighboring elements like bubble sort, instead it compares every pair of positions.

codeforcescompetitive-programming
CF 103470A - Oops, It's Yesterday Twice More

The problem statement is missing from your prompt (both the narrative and constraints are blank), so there isn’t enough information to reconstruct the task, edge cases, or solution strategy.

codeforcescompetitive-programming
CF 103470C - Klee in Solitary Confinement

We are given an integer array representing values on a line, and we are allowed to optionally pick one contiguous segment and increase every value inside that segment by a fixed constant k.

codeforcescompetitive-programming
CF 103470B - Puzzle in Inazuma

The problem statement is missing from the prompt, so there isn’t enough information to reconstruct the task, constraints, or required algorithm.

codeforcescompetitive-programming
CF 1034715 - Квантовые вычисления

I can’t reliably write a correct editorial for this yet because the problem statement is missing. “Codeforces 1034715 - Квантовые вычисления” isn’t enough to reconstruct the task, and anything I produce without the full statement would risk inventing…

codeforcescompetitive-programming
CF 1034714 - Подпоследовательность и подмассив

I can’t write a correct Codeforces-style editorial for this yet because the actual problem statement is missing from your prompt.

codeforcescompetitive-programming
TAOCP 7.2.1.2 Exercise 97

Let $n > c_t > \cdots > c_1 \ge 0$ with the constraints from exercise 57 and the additional condition $c_{j+1} > c_j + 1 \qquad (t > j \ge 1).$ Define the shifted variables $d_j = c_j - (j-1), \qquad...

taocpmathematicsalgorithmsvolume-4medium
CF 1034711 - Камень в море

We are given a single integer T that represents time in seconds after a stone is dropped into an infinite grid of cells. The stone creates an evolving pattern starting from one central cell. At time zero, only the starting cell is active.

codeforcescompetitive-programming
CF 1034713 - Ева красит доску

The problem statement section is empty, so there isn’t enough information to write a correct or meaningful editorial. A Codeforces editorial depends heavily on the exact operations, constraints, and output definition.

codeforcescompetitive-programming
CF 1034712 - Фишки на поле

I don’t have the actual problem statement for “Codeforces 1034712 - Фишки на поле” in your prompt, so I can’t produce a correct editorial yet without guessing.

codeforcescompetitive-programming
CF 103476E - Redundant Binary Representations

The problem defines a non-standard way of writing numbers using powers of two, where each power of two can be used 0, 1, or 2 times.

codeforcescompetitive-programming
CF 103476A - Missing Letters

The problem statement section is empty, so there isn’t enough information to derive a correct solution or write a valid Codeforces-style editorial.

codeforcescompetitive-programming
CF 103476D - Planar Tree

I can’t reliably write a correct, full editorial for “Codeforces 103476D - Planar Tree” as-is because I don’t have the actual problem statement or constraints.

codeforcescompetitive-programming
CF 103476B - Julia and Flower Beds

The problem statement is empty in the prompt, so there isn’t enough information to reconstruct the task, constraints, or required output.

codeforcescompetitive-programming
CF 103476C - Divisor Circle

I don’t have the actual statement for Codeforces 103476C - Divisor Circle in the prompt, and I can’t reliably reconstruct the problem from the title alone without risking hallucinating key rules.

codeforcescompetitive-programming
CF 103478H - 莫卡与阿拉德大陆

We are given several circles drawn on an infinite plane. These circles interact only in a very structured way: any two circles are either completely separate, one fully contains the other, or they just touch.

codeforcescompetitive-programming
CF 103478I - 皮卡丘与 PCPC 集训队

We are given a sequence of integers that is claimed to be generated by a linear recurrence with modular reduction. The sequence starts from a known value and evolves using fixed parameters $a$ and $b$, but the modulus $p$ is unknown.

codeforcescompetitive-programming
CF 103478G - Serval 的数学课堂

We are given an array $A$ of length $n$. For every subarray of length at least three, we first compute a modified average: we remove the minimum and maximum element of that subarray and then take the average of what remains.

codeforcescompetitive-programming
CF 103478F - 魔法少女莫卡的诞生

We are given a permutation of length $2n$, meaning it contains every integer from $1$ to $2n$ exactly once. We are allowed to perform swaps of adjacent positions, exchanging the values at positions $i$ and $i+1$. The target condition is not global sorting.

codeforcescompetitive-programming