Educational Codeforces Round 134 (Rated for Div. 2)

6 problems from Educational Codeforces Round 134 (Rated for Div. 2) (contest 1721), difficulty 800-2800. 2/6 solutions verified against sample I/O.

6 items

Educational Codeforces Round 134 (Rated for Div. 2)

Div. 2 | 6 problems | 2/6 verified | Difficulty 800-2800 | 21m 34s

#	Problem	Rating	Tags	Accepted	Time	✓
A	Image	800	greedy, implementation	28,308	3m 11s	✓
B	Deadly Laser	1000	implementation	23,878	4m 23s
C	Min-Max Array Transformation	1400	binary-search, greedy, two-pointers	14,557	2m 13s	✓
D	Maximum AND	1800	bitmasks, dfs-and-similar, divide-and-conquer	7,679	3m 45s
E	Prefix Function Queries	2200	dfs-and-similar, dp, hashing	2,550	3m 4s
F	Matching Reduction	2800	brute-force, constructive-algorithms, dfs-and-similar	514	4m 58s

Practice › Codeforces Solutions › Educational Codeforces Round 134 (Rated for Div. 2) ›

CF 1721F - Matching Reduction

We are working with a bipartite graph where the left side has $n1$ vertices and the right side has $n2$ vertices. Edges are fixed and each edge connects one left vertex to one right vertex.

Practice › Codeforces Solutions › Educational Codeforces Round 134 (Rated for Div. 2) ›

CF 1721E - Prefix Function Queries

We are given a fixed reference string and then asked to process many short query strings. For each query, we temporarily append the query string to the reference, compute the prefix function on the resulting concatenation, and output only the prefix function values…

Practice › Codeforces Solutions › Educational Codeforces Round 134 (Rated for Div. 2) ›

CF 1721D - Maximum AND

We are given two arrays of equal length. One array, call it a, is fixed in place. The second array b can be permuted arbitrarily. After choosing a permutation of b, we pair elements by index and form a new array where each position becomes the XOR of the paired values.

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CF 1721B - Deadly Laser

We are working on a grid where a robot starts at the top-left corner and wants to reach the bottom-right corner using four-directional moves.

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CF 1721A - Image

We are given a tiny image made of four pixels arranged in a 2 by 2 grid. Each pixel is labeled with a lowercase letter, representing its current color. The goal is to make all four pixels end up with the same color using a sequence of painting operations.

Practice › Codeforces Solutions › Educational Codeforces Round 134 (Rated for Div. 2) ›

CF 1721C - Min-Max Array Transformation

We are given two non-decreasing arrays, one original array and one final array. The original array can be “shifted” element by element by adding a non-negative value to each position, producing an intermediate array.