Educational Codeforces Round 124 (Rated for Div. 2)

Solutions for Educational Codeforces Round 124 (Rated for Div. 2) (contest 1651). 4/6 problems verified against sample I/O. Difficulty range: 800-3000.

6 items

Educational Codeforces Round 124 (Rated for Div. 2)

Type: Div. 2 | Problems: 6 | Verified: 4/6 | Rating range: 800-3000 | Time: 10m 1s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Playoff	800	implementation	1m 28s	✓
B	Prove Him Wrong	800	constructive-algorithms, greedy	2m 10s	✓
C	Fault-tolerant Network	1500	brute-force, data-structures, implementation	1m 55s	✓
D	Nearest Excluded Points	1900	binary-search, data-structures, dfs-and-similar	1m 29s	✗
E	Sum of Matchings	2600	brute-force, combinatorics, constructive-algorithms	1m 49s	✗
F	Tower Defense	3000	binary-search, brute-force, data-structures	1m 10s	✓

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CF 1651E - Sum of Matchings

We are given a bipartite graph with n vertices on each side. The vertices on the left are numbered 1 to n and the right n+1 to 2n. Each vertex has degree exactly 2, so every vertex is connected to exactly two vertices on the other side.

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CF 1651F - Tower Defense

We have a one-dimensional tower defense level with n towers lined up along the axis from position 1 to n. Each tower has two attributes: a mana capacity ci and a regeneration rate ri.

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CF 1651D - Nearest Excluded Points

We are given a set of distinct integer lattice points on a 2D grid. For each of these points, we want to “escape” to the nearest grid point that is not part of the input set, where distance is measured in Manhattan metric.

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CF 1651B - Prove Him Wrong

We need to construct an array of length n such that applying the given operation to any pair of positions never decreases the total sum of the array. Suppose we choose two values x and y.

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CF 1651C - Fault-tolerant Network

We have a network of computers arranged in two rows, each containing n computers. Each computer has an associated grade, represented as an integer. Computers in the same row are initially connected to their immediate neighbors, forming two independent chains.

Practice › Codeforces Solutions › Educational Codeforces Round 124 (Rated for Div. 2) ›

CF 1651A - Playoff

We are simulating a knockout tournament where the number of players is a power of two. Players are labeled from 1 up to $2^n$, and they repeatedly face off in rounds until only one remains.