Educational Codeforces Round 128 (Rated for Div. 2)

Solutions for Educational Codeforces Round 128 (Rated for Div. 2) (contest 1680). 2/6 problems verified against sample I/O. Difficulty range: 800-2600.

6 items

Educational Codeforces Round 128 (Rated for Div. 2)

Type: Div. 2 | Problems: 6 | Verified: 2/6 | Rating range: 800-2600 | Time: 19m 23s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Minimums and Maximums	800	brute-force, math	8m 48s	✗
B	Robots	800	implementation	1m 31s	✓
C	Binary String	1600	binary-search, greedy, strings	1m 29s	✓
D	Dog Walking	2400	brute-force, greedy, math	2m 40s	✗
E	Moving Chips	2000	bitmasks, dp, greedy	2m 15s	✗
F	Lenient Vertex Cover	2600	dfs-and-similar, divide-and-conquer, dsu	2m 40s	✗

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CF 1680A - Minimums and Maximums

We are asked to construct arrays called beautiful arrays. A beautiful array is one in which the number of elements equal to the minimum value falls between two given bounds, $l1$ and $r1$, and the number of elements equal to the maximum value falls between two bounds, $l2$ and…

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CF 1680F - Lenient Vertex Cover

We are asked to find a lenient vertex cover for a connected undirected graph. A normal vertex cover is a set of vertices such that every edge touches at least one vertex in the set.

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CF 1680D - Dog Walking

We are given a sequence of movements of a dog along an infinite line. Each minute, the dog moves a certain distance. Positive numbers move it to the right, negative to the left, and zero indicates unknown movement where we can pick any integer in the range $[-k, k]$.

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CF 1680E - Moving Chips

We are given a $2 times n$ board where some cells contain chips, represented by '', and others are empty, represented by '.'. Our task is to move chips so that exactly one chip remains on the board.

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CF 1680B - Robots

We are given a small rectangular grid, with each cell either empty or containing a robot. Robots can move simultaneously in one of four cardinal directions, and if any robot tries to leave the grid, it explodes.

Practice › Codeforces Solutions › Educational Codeforces Round 128 (Rated for Div. 2) ›

CF 1680C - Binary String

We are given a binary string and we are allowed to cut it in a very specific way: we choose some prefix and suffix to remove, leaving a single contiguous substring in the middle. The remaining substring is what we “keep”, while everything outside it is considered removed.