2024-2025 CTU Open Contest

12 problems from 2024-2025 CTU Open Contest (contest 105442), difficulty -. 12/12 solutions verified against sample I/O.

12 items

2024-2025 CTU Open Contest

Special | 12 problems | 12/12 verified | Difficulty - | 12m 47s

#	Problem	Tags	Time	✓
A	Flag Bearer		1m 15s	✓
B	Cowpproximation		1m 18s	✓
C	Reptile Eggs		1m 18s	✓
D	Fishception		58s	✓
E	Pigpartite Giraffe		1m 20s	✓
F	Hamster		56s	✓
G	Pray Mink		57s	✓
H	Ornithology		57s	✓
I	[P	k Cutting](https://codeforces.com/problemset/problem/105442/I)
J	Rabid Rabbit		1m 3s	✓
K	Fellow Sheep		54s	✓
L	Watchdogs		56s	✓

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CF 105442L - Watchdogs

We are given a town modeled as a tree with N locations connected by N − 1 roads. Because it is a tree, there is exactly one simple path between any two places. Each mouse is defined by two special nodes A and B, and it only moves along the unique path between them.

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CF 105442J - Rabid Rabbit

We are given a line of rabbit hutches, each containing some number of rabbits. For each query, we are handed a contiguous segment of this line, and Leonardo is only allowed to operate inside that segment. Each “day” he chooses a pair of distinct hutches inside the segment.

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CF 105442K - Fellow Sheep

We are given a long chain of identical structural segments. Each segment contains five directed paths, labeled A through E. Every path has a gate somewhere in the middle that allows only a limited number of sheep to pass before it permanently closes.

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CF 105442I - P||k Cutting

We are given an array of integers representing daily “cookie offers”. Each interval is a contiguous block of days, and for any chosen interval two different payment rules are applied to the same segment.

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CF 105442H - Ornithology

We are given two parallel rows of positions, both indexed from 0 to n − 1. The first row is already populated with birds, where multiple birds may start from the same position. The second row is initially empty, but each bird has a fixed target position on that second row.

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CF 105442G - Pray Mink

We are given a single integer written on a cookie tray, and we should think of it as a sequence of digits placed side by side.

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CF 105442E - Pigpartite Giraffe

We start with two disjoint groups of animals, pigs and giraffes. Initially, each pig may “talk” to some giraffes, and this relationship is symmetric, so a pig is connected to a giraffe if and only if that giraffe is connected back to that pig.

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CF 105442F - Hamster

We are given a rectangular grid where each cell contains a non-negative number representing larvae. A hamster starts at the top-left cell and must reach the bottom-right cell. At every step it moves to a neighboring cell that shares an edge, and it never revisits any cell.

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CF 105442D - Fishception

We are given a large collection of points on the plane. These points come from repeatedly relocating the corners of a rectangle over several days.

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CF 105442C - Reptile Eggs

We are given a line of eggs represented by a string. Each position contains a single concrete type, so the string is just a sequence of lowercase letters. Alongside this, we are given a pattern written in a restricted regular-expression language.

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CF 105442B - Cowpproximation

We are given several cows on a plane. Each cow starts at a fixed coordinate and occupies a circular region with a given radius. Every cow can move in any direction with speed at most one meter per second, and they all move simultaneously.

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CF 105442A - Flag Bearer

Each message consists of several symbols drawn as small 9 by 9 pictures. Every picture encodes one English letter using a semaphore system: a central pivot cell and two “arms” that extend from it in two distinct directions among the eight compass directions.