Codeforces Round 168 (Div. 1)

Solutions for Codeforces Round 168 (Div. 1) (contest 274). 2/2 problems verified against sample I/O. Difficulty range: 1500-1800.

2 items

Codeforces Round 168 (Div. 1)

Type: Div. 1 | Problems: 2 | Verified: 2/2 | Rating range: 1500-1800 | Time: 4m 42s

Problem Name Rating Tags Solve Time Verified
A k-Multiple Free Set 1500 binary-search, greedy, sortings 1m 14s ✓
B Zero Tree 1800 dfs-and-similar, dp, greedy 3m 28s ✓
Practice › Codeforces Solutions › Codeforces Round 168 (Div. 1) ›

CF 274A - k-Multiple Free Set

We are asked to find the largest subset of a given set of positive integers such that no element in the subset is exactly k times another element in the subset.
codeforces competitive-programming binary-search greedy sortings May 29, 2026
Practice › Codeforces Solutions › Codeforces Round 168 (Div. 1) ›

CF 274B - Zero Tree

This problem asks whether a matrix returns to its original form after repeatedly applying cyclic row shifts. The matrix has m rows and n columns. Every operation affects all rows simultaneously, but the direction depends on the row index.
codeforces competitive-programming dfs-and-similar dp greedy trees May 29, 2026