CodeCraft-22 and Codeforces Round 795 (Div. 2)

Solutions for CodeCraft-22 and Codeforces Round 795 (Div. 2) (contest 1691). 5/6 problems verified against sample I/O. Difficulty range: 800-2500.

6 items

CodeCraft-22 and Codeforces Round 795 (Div. 2)

Type: Div. 2 | Problems: 6 | Verified: 5/6 | Rating range: 800-2500 | Time: 19m 26s

Problem Name Rating Tags Solve Time Verified
A Beat The Odds 800 brute-force, greedy, math 1m 53s ✓
B Shoe Shuffling 1000 constructive-algorithms, greedy, implementation 1m 58s ✗
C Sum of Substrings 1400 brute-force, constructive-algorithms, greedy 8m 8s ✓
D Max GEQ Sum 1800 binary-search, constructive-algorithms, data-structures 1m 57s ✓
E Number of Groups 2300 data-structures, dfs-and-similar, dsu 3m 12s ✓
F K-Set Tree 2500 combinatorics, dfs-and-similar, dp 2m 18s ✓
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CF 1691C - Sum of Substrings

We are given a binary string of length $n$ and we want to minimize a sum computed from all consecutive pairs of digits. Each pair of digits $si s{i+1}$ is treated as a decimal number, so "10" counts as ten, "01" as one, and so on.
codeforces competitive-programming brute-force constructive-algorithms greedy math strings Jun 9, 2026
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CF 1691F - K-Set Tree

We are given an undirected tree with $n$ vertices. For every choice of a root $r$, the tree becomes rooted. For every $k$-element vertex set $S$, we look at the smallest rooted subtree that contains all vertices of $S$. A rooted subtree is not just any connected subgraph.
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CF 1691E - Number of Groups

We are given a set of segments on the number line, each colored either red or blue. Each segment occupies a continuous interval from li to ri, inclusive.
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CF 1691D - Max GEQ Sum

We are asked to determine whether, for a given integer array, the maximum value in any contiguous subarray is at least as large as the sum of that subarray.
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CF 1691B - Shoe Shuffling

We are given a sorted list of shoe sizes for a group of students. Each student initially owns exactly one pair of shoes, and we want to redistribute these shoes among the students so that everyone receives exactly one pair.
codeforces competitive-programming constructive-algorithms greedy implementation two-pointers Jun 9, 2026
Practice › Codeforces Solutions › CodeCraft-22 and Codeforces Round 795 (Div. 2) ›

CF 1691A - Beat The Odds

We are given a sequence of integers, and we need to remove as few numbers as possible so that every pair of consecutive numbers in the remaining sequence sums to an even number. The sum of two numbers is even if both numbers are even or both are odd.
codeforces competitive-programming brute-force greedy math Jun 9, 2026