brain

We are given an array of problem difficulties, and we want to count how many valid ways exist to split the index range from 1 to n into contiguous segments.

We are given two closed integer intervals. One interval describes the possible values of an integer $a$, and the other describes the possible values of an integer $b$.

Working

We are asked to design, for each test case, a connected simple graph that uses exactly $m$ edges and as few or as many vertices as we choose (but at most $m+1$), under a degree constraint $d$.

We are given a string that looks like a bracket sequence containing round and square brackets. This string is not necessarily a valid bracket sequence.

We are given a line of hooks indexed from 1 to n. The two boundary hooks, 1 and n, are considered already used before the process begins. After that, the system repeatedly performs a deterministic operation on the remaining unused hooks.

The setting is a very small round robin tournament with four teams, which we can think of as nodes A, B, C, and D, and a complete set of six possible matches between every pair of teams.

The system models a park with multiple lanterns, each lantern holding a lamp that eventually burns out. Every lamp has a known lifetime, so each lantern can be thought of as producing an “expiration event” at a specific time.

We are given a sequence of events ordered by time. At each time moment, the cat catches some number of mice. Multiple catches may happen at the same time moment, so the raw input can contain repeated timestamps with associated counts.

We are simulating a simple interaction between a cat and a moving glowing point on a 2D grid. The point changes position step by step, and after each move we evaluate what the cat does in response.

We are given a string consisting of uppercase Latin letters, and we are interested in counting how many ordered subsequences of the form “C-A-T” exist inside it.

We are given several independent 8 by 8 character grids. Each grid is mostly filled with dots, but somewhere inside it a single word is hidden. The word is written straight down in exactly one column, occupying consecutive rows without interruption.

The input describes positions of a rook on a standard 8 by 8 chessboard. Each position is given in algebraic notation, where a letter from a to h identifies the column and a digit from 1 to 8 identifies the row.

I don’t have the actual statement of Codeforces 104922I - Paired roads, so I can’t reliably reconstruct the problem or derive a correct editorial.

I can’t write a correct editorial for this yet because the actual problem statement is missing. Right now I only see the title “104922H - Lunch”, but no description of the input, output, or rules.

I can’t reliably write a correct Codeforces editorial for “104922G - Space accident” because the actual problem statement (what is being asked, what the input/output represent, and the constraints) is missing here.

The problem statement section is empty, so there isn’t enough information to reconstruct what Codeforces 104922D is asking.

I can’t reliably write an editorial for Codeforces 104922F - Tournament because the actual problem statement is missing from your prompt. Right now I don’t know: - what structure the “tournament” refers to (bracket, graph, game outcomes, DP on tree, etc.

I can’t write a correct editorial for this yet because the actual problem statement (what “Colorful graph” asks for, input format, and output definition) is missing from your prompt.

You are right to pause here: the problem identifier is misleading on its own, and without the actual statement it is impossible to write a correct editorial.

I’m missing the actual problem statement for Codeforces 104922A - “You need to train more” in your prompt, and I can’t reconstruct it reliably from the title alone.

I can’t reliably write a correct editorial for this yet because the actual problem statement is missing. “Codeforces 104922B - Yet another queries” is not enough on its own, and there are multiple possible problems with similar names and formats.

We are given an undirected connected graph where each edge must be assigned one of two colors, red or blue. After coloring, we want a strong reachability property: between every pair of vertices, there must exist a walk that alternates colors on consecutive edges.

We are repeatedly interacting with a collection of “task providers”, called slayer masters. Each master has a fixed list of tasks. A task has a frequency weight, a duration, and an XP rate per minute.

We are given a directed graph on vertices labeled from 1 to n, with a distinguished root at vertex 1. The task is to choose a set of directed edges that forms a spanning arborescence rooted at 1, meaning every vertex is reachable from 1, and every vertex except the root has…

We are given a rooted tree with root fixed at node 1, and we are told which vertices are leaves of this tree. From this set of leaves, we will choose exactly k of them, for every k from 1 up to the total number of leaves.

We are given a directed graph with a designated source node and sink node. Instead of choosing a discrete set of paths or integer flows, we assign a real-valued flow to every edge, possibly negative, as long as flow conservation holds at every vertex and the net flow from…

We are given a rooted binary tree where each internal node combines the results of its two children using a fixed operation: the vector cross product in three dimensions.

We are given a number $n$, and for each test we must either construct two positive integers $a$ and $b$ (both below $2^{60}$) or report that no such pair exists. The required condition mixes addition and bitwise XOR in a way that forces carries and bit cancellations to interact.

We are given a set of files, each file having two independent total orders defined on it. One order is by file name, the other is by creation date. The file names order is fixed and already represented by indices from 1 to n.

The sequence starts from a single binary digit string and evolves by repeatedly describing the previous string in terms of runs of identical digits. Each run is converted into two parts: the length of the run and the digit being repeated.

We are given two rooted trees that share the same set of leaf vertices labeled from 1 to k. Every other vertex is an internal node.

We are given a fixed sequence of 11 words, each representing a button press in a game cheat code. Separately, there is a known reference sequence, the Konami Code, which is also 11 inputs long.

We are given a small array of integers, each test case independent. From that array, we consider every possible subset of elements except that we are not allowed to take the entire array.

We are asked to count sequences of length $N$ where each position contains a “rank” chosen from a fixed ordered set of 13 denominations: Ace is the smallest, followed by 2 up to King.

We are given an $N times M$ grid where each cell contains a binary value. A value of 1 means the tile is currently flipped, and 0 means it is already correct.

Each slot machine behaves like a stochastic reward generator. When you pull a machine once, it returns one value from a fixed finite set, each value having a known probability. Those probabilities do not change over time and every pull is independent of previous pulls.

We are given several independent test cases. In each test case, a line of people stands in a fixed order, where each person is either from Uptown or Downside.

We are given a starting point that is always the number 1, and we are allowed to build a sequence by repeatedly multiplying the current value by any positive integer.

We are given a house number written as a string of digits. The city has a symmetry rule: when you rotate the number by 180 degrees, it must still form a valid readable number using the same digit system. Only a restricted set of digits survives rotation: 0, 1, 6, 8, and 9.

We are placing shrimps on an $n times m$ grid, where each cell can either contain a shrimp or be empty. Each configuration is just a binary matrix. The grill has a rule that only activates locally on every $2 times 2$ subgrid.

We are given multiple test cases. Each test case consists of a line of people standing in a row, where each person belongs to one of two groups, encoded as U or D.

We are interacting with a hidden circular array of length $N$, where $1 le N le 2 cdot 10^5$. Each position on the circle contains an integer value, and these values are strictly increasing as we move around the circle in order: $s1 < s2 < dots < sN$.

We are counting sequences of length $N$ formed from a fixed set of card ranks. The ranks behave like a total order: Ace is the smallest, then 2 up to King. The key restriction is on how consecutive cards are allowed to change. The first card in the sequence can be any rank.

The dance floor is a rectangular grid where each cell contains a person who is either in a normal orientation or flipped. We want to transform the entire grid into all zeros by applying a specific operation any number of times.

We are given a small array of integers for each test case. From this array we may choose any subset of elements, but we are explicitly forbidden from choosing the full array. The subset can even be empty.

We are given several slot machines, each producing a random reward when pulled. Each machine has its own fixed probability distribution over a small set of possible reward values.

We are given a set of distinct target numbers. We start from the value 1 and are allowed to build a sequence by repeatedly multiplying the current value by any positive integer.

There are several organizers, each one getting progressively more late as meetings go on. The delay of each organizer does not stay fixed: for a given person, their lateness in the first meeting is known, and then every subsequent meeting they become even later by a fixed…

We are given a binary string for each test case, where each position represents a city that either supports Busy Beaver (1) or Lazy Lemur (0). We are allowed to partition this array into exactly $K$ contiguous nonempty segments, and each segment is considered a district.

We are given several buildings placed around a circle. Each building has a fixed position on the circle and a height. There is also a special building at the center whose height is not fixed in advance; instead, it is given separately for each query.

We are building a tree one vertex at a time. Initially there is only vertex 1. Each query adds a new vertex and connects it to some existing vertex, so the structure always remains a rooted-growing tree.

The grid can be thought of as a board where some cells are blocked, some are irrelevant empty space, and some cells are special anchors marked with o. Every o cell must become the center of an L-shaped tromino.

We are given a list of integers arranged in a line. Two players repeatedly compress this line until only one number remains. A move always picks two adjacent elements, removes them, and replaces them with a single value derived from the pair.

Each test case describes a small system of polynomial equations over positive integers. Every variable is one of the first letters of the alphabet, and each equation is a sum of terms where a term is a coefficient multiplied by a product of variables.

We are given the radius of a circle, and we are asked to construct a square that has exactly the same area as that circle. The task is not geometric construction in the classical sense, but a direct numerical computation: we must output the side length of such a square.

We are given a binary tree over the numbers from 1 to N, but the tree structure is not explicitly provided. Instead, we are told three traversal descriptions.

We are given a collection of rectangular tiles, each tile having an integer side lengths $Ak times Bk$ where both sides are at most 3, and the tile may be rotated. All tiles together have total area exactly $3N$.

We are simulating a selection process over a dynamic set of players labeled from 1 to N. Initially all players are available. Two leaders alternate turns.

We are given the vertices of a simple non-self-intersecting polygon in order. Think of it as a rigid flat tabletop whose mass is uniformly distributed across its area.

Codeforces 104945J: Olympic goodies

Each player rolls multiple independent dice, and the final score is the sum of all face values shown by their dice. Every die is fair, but different dice may have different numbers of sides, so each die contributes a uniform integer in a different range.

Each dish comes with two attributes: a taste score and a plating score. Each person also comes with two preferences, which act as weights for those same two attributes.

We are given a sequence of heights along a straight hiking trail. Each index represents a milestone placed at equal horizontal spacing, and each milestone has a distinct altitude.

We start with a permutation of size $N$, where person $i$ initially holds a flag of some color $pi$. A move consists of choosing any two positions and swapping the flags they hold.

Each team in this competition is described by a name, a count of solved programming problems, and six scores coming from trampoline exercises. The final result of a team is a single total score formed by combining two independent parts.

We are given a collection of metro lines, where each line can be seen as a subset of stations from a fixed universe of size up to 18. A line is fully described by which stations it stops at.

We are given a sequence of cards held in a hand. Each card has a suit among five types, ordered by priority as silver, white, emerald, red, and cyan, and each card also has a numeric label within its suit.

Each country can be represented in one of two ways. Either Alice prepares a full flag drawing, which requires buying all the colors that appear in that country's flag, or she avoids drawing that flag entirely and instead uses a single pin for that country.

We are given a small grid of numbers. From this grid, we are allowed to repeatedly delete entire rows or entire columns. Each deletion permanently removes all values in that row or column, and the remaining parts of the table stay intact.

I can’t write a correct editorial yet because the actual problem statement is missing. Right now I only see the title “Выбор столицы” (“Choosing a capital”), but there is no description of the graph, input format, constraints, or what needs to be optimized.

We are given a simplified model of an airplane cabin where seats are arranged in rows, and each row contains six seats indexed from left to right. The middle of each row is a fixed aisle between the third and fourth seat.

I can’t reliably reconstruct the actual task from just the title “Битоническая последовательность” and the ID, because Codeforces has multiple problems around bitonic sequences with very different requirements (LIS-based, rearrangement…

The tree structure is fixed: each node has up to two children and node 1 is the root. What changes over time is a label attached to every node, chosen from three values that decide whether that node is visited before its subtrees, between them, or after them.

We are given a multiset of numbers, represented as an array. The task is to partition all elements into groups of exactly three elements, with no element left unused.

I can write the full editorial in exactly the format you requested, but I’m missing the actual problem statement.

I don’t actually have the problem statement for “Codeforces 1049506 - Бактерии” in your prompt, and I can’t reconstruct the task reliably from just the title and metadata.

We are given a long sequence of years, each year carrying two integer values: one describing the number of “good” events and another describing the number of “bad” events. Two years can be related in two different direct ways.

We are given a collection of grimoirs, each one carrying two attributes: a difficulty value and a potential value. The order in which they were purchased is fixed and matters as a final tie-breaker. At each of $n$ moments, we must select exactly one unused grimoir.

The continent is a tree of cities. Traveling along any road takes exactly one year, and because the graph is a tree there is a unique simple path between any two cities.

Codeforces 104959B: Фрирен и барьер

We are given several independent test cases. In each one, we receive a list of integers, all written using exactly k binary bits. The value of each number is therefore in the range from 0 to 2^k - 1.

We are given a tree of rooms. Each room initially contains a fixed number of pancakes, and every corridor between two rooms also contains pancakes.

We are given a straight line of metro stations connected by consecutive segments, where segment $i$ connects station $i$ and $i+1$ and has a travel cost $ci$.

We are given a number of identical sticks, and the task is to form rectangular grid structures using exactly all of them. A grid of size $n times m$ is a rectangle subdivided into unit squares, where every unit edge in the grid is represented by a stick.

We are given a cycle of n houses. Each house is placed on a circle, so every house has a natural notion of moving left or right along the cycle. We are allowed to choose a parameter k.

We are maintaining a multiset of large non-negative integers under three kinds of operations, and after each operation we must report the bitwise XOR of all current elements. The operations are dynamic in two different ways.

We are asked to count how many different ways a fixed amount of money $N$ can be paid exactly using banknotes of denominations 50, 100, and 200, where each denomination can be used any number of times.

Each pizza comes with a structure that can be interpreted as a small graph. There is a central point and a ring of $si$ slice vertices. Every slice vertex is connected to the center with cost $qi$, and each slice is also connected to its two neighbors on the ring with cost $ci$.

We are given a sequence of students arriving in a fixed order, and each student consumes a specific number of pizza slices. There are K pizzas prepared, and every pizza must have the same number of slices, call this value X.

We are given two finite point sets in the plane. One set represents topping points, and the other represents crust points. Every valid pizza slice is formed by choosing the origin together with any two crust points, forming a triangle whose third vertex is fixed at the origin.

We are given a large set of distinct points on a grid. Each point represents a pepperoni slice, and we are asked to construct a straight line such that the line passes very close to many of these points.

We are arranging a permutation of pizzas labeled from 1 to $n$, where each label is the radius of that pizza. Once we choose an order, we look at all pairs of positions in the stack: if a larger pizza appears below a smaller one, we call that pair “proper”.

We are given a line of people before Shelly arrives. Each of those people can take food from a shared pool consisting of pizza slices, tacos, and sauces. Every person can take up to two items freely, where an item is either a pizza slice or a taco.

We are given a pile of pizzas, each pizza cut into 8 identical slices. With $n$ pizzas, the total number of slices is fixed at $8n$. These slices must be distributed among $m$ friends. The distribution has two constraints at the same time.

The pizza is represented as a square grid of size $N times N$, where each cell contains a single alphabet character. Among these characters, only two symbols matter for us: uppercase ‘P’ and lowercase ‘p’.

Each pizza consists of a circular arrangement of slices plus a center point. Every slice has a cost parameter and the crust around the pizza also has a cost parameter.

Codeforces 104973A: Median

We are given a collection of databases arranged in a line. Each database behaves like a queue with a fixed capacity. We also have a sequence of operations, and each operation takes a value and pushes it into every database whose index lies inside a given interval.

We start with an array a whose elements contribute to a total sum we want to maximize. We are allowed to delete elements from a, but deletions are not arbitrary: each deletion is triggered by choosing a position from a second array b, and removing the corresponding indexed…