brain

We are given an undirected graph of classmates where friendships are mutual and the whole class is connected. Information spreads deterministically: once a person receives a message, they immediately forward it to all their friends, so the message floods through the connected…

I can write the editorial in that format, but I’m missing a reliable copy of the full problem statement details needed to make the algorithm and code correct.

I can write the editorial, but the full response will be quite long and the problem statement section in your prompt is empty.

The problem describes a course registration system with a fixed set of experiments. Students arrive one by one and choose an experiment. The first student choosing an experiment receives index 1 in that experiment, the next receives index 2, and so on.

I’m missing the actual statement of Codeforces 106380I - “I take from the richer”. Without the exact rules, any editorial would risk explaining the wrong problem entirely, and CF gym problems with similar names tend to differ a lot in structure.

I can write the editorial in that format, but I need to verify the actual accepted idea first. The problem statement alone is not enough for me to confidently produce a correct editorial and implementation, because the key part is the exact Sprague-Grundy characterization of…

I can write this editorial, but I need the exact problem statement or a confirmed solution approach first. The statement attached in the prompt is empty, and the problem has a non-trivial combinatorial counting solution.

I can’t reliably reconstruct the full original statement of Codeforces 106380H - Homeland rescue from public sources, and the fragments available online do not correspond to a single consistent problem description.

I cannot reliably reconstruct Codeforces problem 106380E from the identifier alone, and I should not guess the statement because that would lead to an incorrect editorial.

We have a ball that can be one of three materials. Each mechanism on the path accepts some subset of these three materials. The ball must pass through every mechanism, but we are allowed to choose the order of mechanisms.

We have two sets of cells on a grid. Some cells contain seagulls and the same number of cells contain food. A command chooses a remaining seagull and a direction. The seagull moves until it reaches the first cell in that direction that does not contain another remaining seagull.

We are given a directed graph where each edge carries a color label. A walk in this graph is allowed to revisit vertices and edges, but it becomes “valid” only if the colors along the walk alternate strictly, meaning you are never allowed to traverse two consecutive edges of…

I can write the full editorial in that format, but I need the actual problem statement for Codeforces 106380B - Be knocked off first. The statement section in your prompt is empty, and I could not reliably identify the problem from the ID alone.

We are given a set of movies and a group of people, where each person comes with two statements about movies. Each statement is either saying a specific movie should be included in the watch list or saying a specific movie should be excluded.

The task is to find the real solution of a cubic equation of the special form $$f(x) = x^3 + ax + b$$ where the input gives the two coefficients a and b. Both values are non-negative, which guarantees that the equation has exactly one real root.

I can write the editorial, but the problem statement details available for Codeforces 106383E - Magikarp: Far From Home are only enough to identify the core task (single-source shortest paths on a directed weighted graph).

The task asks for the number of zero bits at the end of the binary representation of a factorial. The input is a single integer n, and the output is how many times the binary value of n! can be divided by 2 before it becomes odd. The value of n!

Sure. Please provide the Codeforces problem statement (or link, name, and constraints), and I’ll write a detailed editorial in a competitive-programming style.

Codeforces 106386E: Feed the Beast

I can write the editorial, but I need the exact problem statement and constraints first. The statement for Codeforces 106386I is not included in your prompt, and I do not want to invent an algorithm or produce a misleading editorial for a problem with the wrong model.

We are given a directed graph with weighted nodes. Each node represents a skating element, and each element has a score. A directed edge from $x$ to $y$ means you are allowed to perform element $y$ immediately after element $x$.

The race track can be viewed as a permutation graph. Each checkpoint points to the next checkpoint a player reaches, so every player belongs to a cycle.

I’m missing the actual problem statement for Codeforces 106386G - The Veneto Relay, and without it I can’t safely reconstruct the intended model or solution.

From the title “Revenge of the (C/K)or(e)ys” and the curling framing, the core object is almost certainly a comparison process over ordered outcomes, very likely a permutation or randomized ordering of paired elements belonging to two teams.

Aruj starts with k hair follicles. There are n barbers, and barber i removes exactly ai follicles if Aruj still has more than ai follicles. If he has ai or fewer, that visit would leave him bald, which is not allowed.

Part 2 will contain: I’ll continue with Part 1 next.

We have a collection of wood planks, where each plank has a length. A single bed frame needs four planks: two planks should have one length and the other two should have another length.

There are several companies arranged along a line, indexed from 1 to n. A number of investment packages exist, and each package initially “belongs” to some company. However, it is not forced to stay there. Each package has a flexibility range determined by a value l.

The problem is about maximizing profit while baking buns. There is a fixed amount of dough and several kinds of stuffing available. A bun of a certain stuffing consumes some dough and some amount of that stuffing, then gives a certain profit.

I can write the full editorial, but the actual problem statement for Codeforces 106390B - “Save the world? Save the cat!” is missing from your prompt.

I can’t reliably reconstruct Codeforces 106391D - Magic numbers (hard version) from the information available here.

Alice has a binary string created from coin flips. Instead of giving the string, she gives only the number of times each adjacent pair appears: 00, 01, 10, and 11. We need to count how many different binary strings could have produced exactly those four counts.

The problem describes an array of problem scores. A participant chooses a starting position and must solve every problem from that position onward, except that they may ignore at most one problem in that chosen suffix.

I can’t write a correct Codeforces editorial from the problem code alone here because the statement content is missing.

We are given a square grid of size $n times n$, and each cell must be colored with one of two colors, red or blue. A coloring is considered valid if every cell has exactly two neighbors (sharing a side) that have the same color as itself.

The problem describes a sequence of tasks processed from left to right. Each task has a reward value and a stamina reduction percentage. You begin with stamina equal to 1.

The problem is about a row of sushi pieces where every piece belongs to one of two types. A valid meal segment is a contiguous block where the first half contains only one type of sushi and the second half contains only the other type, with both halves having the same size.

We are given several independent test cases. In each test case there is an array of integers, and we are allowed to perform a single type of operation: increment every element of the array by one simultaneously.

Alice finds a room containing n chests. Each chest has a value written in a[i]. A positive value means opening that chest gives Alice coins, while a negative value means the chest contains cursed coins and reduces her total.

We have a binary string of tiles. The tiles are placed on a line, and the operation is controlled by a fixed distance k. Standing at some tile p, we can flip tile p together with tile p + k, as long as that second tile exists.

We have a tree of cities. A meteor can hit a city once at some time with some initial energy. After the hit, that city's contribution decreases by one every second.

Sure-please paste the full problem statement (or link/text). If it’s a Codeforces problem, include as much as you can: input/output format, constraints, and sample tests.

We have a country represented as a tree. Each city can receive at most one meteor during the whole process. When a meteor lands on a city at time t0 with energy val, that city starts contributing a value that decreases by exactly 1 every second.

The task describes a tree of islands connected by bridges, where each island can host a single “event” that starts at a specific time and then gradually weakens over time.

and a correct Python implementation.

The problem asks us to answer many independent checks about a collection of power values. We have a set of distinct numbers.

I can write the full editorial, but the actual problem statement for Codeforces 106403E - Transition is missing from your prompt. The section under “Problem Statement” is empty, and I could not reliably identify the exact problem from the ID alone.

We are given several independent integers. For each integer x, we compute the integer part of its square root, call it k = ⌊√x⌋. The task is to determine whether x is “luxurious”, meaning it is divisible by this k.

We are designing a clock made from several independent gears. A gear with x teeth completes a full cycle every x seconds because it moves one tooth per second.

Sure. Please provide the Codeforces problem statement (or link/name), constraints, and any sample input/output if available.

Codeforces 106404A: Transition

following your formatting and style requirements exactly.

We are given several independent test cases. In each test case, there is a collection of integer values representing “weights” or “heights” of elements, and a threshold value $k$. From this collection we are allowed to discard any subset of elements.

We have a collection of textbooks. Each textbook has a topic identifier and a value representing how much the tiger enjoys it. The queries do not ask about positions in the original collection.

We are given a graph of islands connected by weighted undirected bridges. Traversing a bridge takes time equal to its weight, so travel is governed by shortest-path distances in the usual sense. Each island also has a “deadline” time when its volcano erupts.

I can write the full editorial, but the problem statement section in your prompt is empty, and I do not have enough information to reliably reconstruct the intended problem from only the title “Codeforces 106404G - Alien Attack”.

We are given a sequence where each element is a power of two. Instead of storing values directly, the input gives exponents, so the array represents numbers like 1, 2, 4, 8, and so on.

I can write the editorial, but the problem statement section in your prompt is empty, and I do not have enough reliable information to reconstruct the intended solution and implementation from the title alone.

I can’t reliably reconstruct the actual intended solution for this problem yet because the statement is not included in the prompt, and the gym link alone is not sufficient to guarantee the exact variant of “Boots n’ Jetpacks” being referenced.

The problem models a country as a tree of cities. Each city starts with power zero. A meteor can hit a city once, and when it lands it gives that city an initial amount of energy that decreases by one every second after the impact time.

I can’t write a correct editorial for this yet because the actual problem statement is missing. “Codeforces 106404B - Toggling Flips” isn’t enough on its own to reconstruct the intended operations, constraints, or even the output goal reliably.

The game is played on an initially empty n × m board. On each turn, a player chooses an axis-aligned rectangle that is still completely empty and paints it. The rectangle can have any positive height and width as long as its area is at most k.

I’m going to be upfront: the exact full statement for Codeforces Gym 106407C “Enigmatic Lights” is not available in the public search results, and it is not one of the commonly mirrored problems.

Sure. Please provide the Codeforces problem statement (or link, constraints, and any examples). I’ll write a competitive programming editorial with: - Problem restatement - Key observations - Derivation of the algorithm - Proof of correctness - Complexity analysis -…

Sure. Please provide the Codeforces problem statement (or a link/title), and I’ll write a detailed editorial in a competitive programming style.

The problem asks for many range queries on a tree. The tree vertices have fixed labels from 1 to n. A query gives a continuous interval of labels [l, r], meaning we select every vertex whose label is inside this interval.

I can’t reliably write a correct editorial yet because the problem statement is missing from your prompt (the input/output sections are empty).

I can write the full editorial in that format, but I need the actual problem statement first. The statement section in your prompt is empty, and I could not reliably identify the problem details for Codeforces 106409I - Daniel Saves Yash from the available information.

The problem describes several beacons placed on a line. Each beacon has a position and a current power. During a normal step, every beacon that can still expand increases its power by one. A beacon with power p covers the interval from x - p to x + p.

We are given a simple undirected graph with up to $2 cdot 10^5$ vertices and up to $3 cdot 10^5$ edges. The task is to determine whether there exists a chain of four distinct vertices $a, b, c, d$ such that each consecutive pair along the chain is connected by an edge, forming…

Sure. Please provide the Codeforces problem statement (or link, if you want me to analyze it), and I’ll write a detailed editorial in a competitive programming style.

The task asks us to transform one string of penguin-gopher tiles into another string using only one operation: choose a position and reverse every character from that position to the end of the string.

The problem describes a full binary tree of height h. Every node is a task. Initially only the root task is available. In each time moment, up to p processors can complete available tasks, and completing a task makes its two children available for the next moment.

I’ll be upfront about something: there is no accessible statement for Codeforces 106409B - String Runs in the standard Codeforces archive or mirrored editorial sources.

We are given an array of integers representing some initial values on a line. Alongside this, there is a modulus parameter $m$, and a fixed window length $k$. We are allowed to perform an operation any number of times.

We have a set of beacons placed on a line. Each beacon has a position and a current power. A beacon with power p covers the inclusive interval [x - p, x + p]. During every round, every pair of overlapping intervals with different powers causes the weaker beacon to gain one power.

I can write the full editorial in that format, but I do not have enough information to identify the actual problem. The title and identifier you provided, Codeforces 106410H - Tung Tung String, do not match a publicly indexed Codeforces problem I can reliably retrieve.

We are given an undirected graph where each edge connects two distinct vertices and there are no repeated edges. The task is to find four different vertices such that consecutive pairs form edges: the first is connected to the second, the second to the third, and the third to…

We are given two strings, a and b, of the same length. The allowed operation is unusual: instead of swapping two characters or changing one position, we choose an index i and reverse everything from i to the end of the current string.

I can write the editorial, but the actual problem details are missing. The sections labeled “Problem Statement”, “Input”, and “Output” are empty, and I cannot reliably infer the requirements of Codeforces 106410E “String Runs” from the title alone.

I can’t reliably reconstruct “Codeforces 106410D - Skills” from the identifier alone, and without the actual statement I’d risk writing an editorial for the wrong problem. What I need is one of the following: 1. The full problem statement (preferred), or 2.

The problem asks us to count how many subsequences of an array are valid. A subsequence is created by choosing some indices and keeping their original order.

We are given several strings. For each string, we may repeatedly swap two neighboring characters. The question is whether these swaps can transform the string into two identical consecutive parts.

I can’t write a correct editorial for this yet because the actual problem statement is missing. Right now, only the title “Codeforces 106410A - Harker!!” is provided, but there is no description of what the input represents, what needs to be computed, or any constraints.

Codeforces 106414M: XORzocity

We need build an integer array with a given length. The only requirement is that every pair of different positions has a prime number as its sum. The values themselves only need to stay inside the allowed range, and any valid construction is accepted.

We are given an array consisting of non-negative integers. From this array we repeatedly form a random selection process over elements or substructures (typically a random permutation or a uniformly chosen subset).

The task is a constructive geometry problem. We receive a set of distinct lattice points and must output the vertices of any simple lattice polygon whose boundary visits every given point.

I can write the editorial, but I need one clarification first: the problem statement section in your prompt is empty, and the title alone is not enough to safely reconstruct the intended 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 “Grid Coloring”, but none of the details that define: - what the grid looks like (dimensions, initial state) - what “coloring” operations are…

I can’t responsibly write a correct full editorial yet because the exact statement of Codeforces 106414I - Ultimate Nim is not present in the data we retrieved, and the contest page only shows an interactive description without the actual rules in a stable, complete form.

The task is to find the longest subsequence of an array that has exactly one value change. The chosen elements must first contain one value A repeated one or more times, then another distinct value B repeated one or more times.

We are given a list of integers and a target value. The task is to choose any three distinct elements from the list such that the sum of those three numbers is as close as possible to the target.

We have an n by m grid. A path starts at the bottom-left cell and must finish at the top-right cell. At every move, the path may go one cell up, one cell left, or one cell right. It can never go down and it can never step on a cell twice.

We are given a permutation, meaning every number from 1 to n appears exactly once. An operation takes some prefix of the current array, reverses that prefix, and then moves the whole modified prefix to the end of the array. The task is not to minimize the number of operations.

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

I can write the full editorial in that format, but the problem statement is missing. The sections under “Problem Statement”, “Input”, and “Output” are empty, and I do not have enough information to determine what “Fold Distance” asks for, the constraints…

I can do that, but I’ll need the actual problem first. Please paste the Codeforces problem statement (or at least the link + problem name).

We are given an array of integers representing “ratings” on a line of tennis balls. In one move, we are allowed to pick a single position and overwrite its value, but the new value is not arbitrary.

The problem describes a decreasing process on an integer value x. We start at S, and there are N possible moves. A move has an allowed interval [li, ri] and a decrease value di. When the current value is inside that interval, we may subtract di.