Educational Codeforces Round 167 (Rated for Div. 2)

Solutions for Educational Codeforces Round 167 (Rated for Div. 2) (contest 1989). 2/6 problems verified against sample I/O. Difficulty range: 800-3000.

6 items

Educational Codeforces Round 167 (Rated for Div. 2)

Type: Div. 2 | Problems: 6 | Verified: 2/6 | Rating range: 800-3000 | Time: 19m 49s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Catch the Coin	800	implementation	6m 38s	✗
B	Substring and Subsequence	1200	brute-force, greedy, strings	2m 17s	✗
C	Two Movies	1400	greedy, math	2m 15s	✗
D	Smithing Skill	1900	brute-force, data-structures, dp	3m 26s	✓
E	Distance to Different	2300	combinatorics, dp, math	2m 12s	✓
F	Simultaneous Coloring	3000	dfs-and-similar, divide-and-conquer, graphs	3m 1s	✗

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CF 1989F - Simultaneous Coloring

We are given a matrix with n rows and m columns, initially colorless. The allowed operations are painting an entire row red or an entire column blue.

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CF 1989A - Catch the Coin

We are given a grid representing the arcade screen with coordinates $(x, y)$, where Monocarp starts at the origin $(0, 0)$. There are $n$ coins scattered on the grid. Each second, Monocarp can move in one of the eight directions (up, down, left, right, and the four diagonals).

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CF 1989D - Smithing Skill

We are given a collection of weapon blueprints and several independent piles of raw material. Each blueprint describes how many ingots are needed to build a weapon and how many ingots are recovered if that weapon is later melted.

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CF 1989E - Distance to Different

We are given an integer array, but we are not asked to build or choose the array directly. Instead, every valid array $a$ over values $1$ to $k$ induces a derived array $b$, where each position $i$ stores how far you must walk left or right from $i$ to encounter a different…

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CF 1989B - Substring and Subsequence

We are asked to construct a string that satisfies two overlapping constraints: it must contain one given string, $a$, as a substring, and another string, $b$, as a subsequence. The difference between substring and subsequence is crucial.

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CF 1989C - Two Movies

Each person has a pair of opinions, one for each of two movies. The opinion is ternary: it contributes either +1, 0, or -1 if that person reviews that movie. We must assign every person to exactly one of the two movies, and this choice determines both movie scores.