Codeforces Round 621 (Div. 1 + Div. 2)

7 problems from Codeforces Round 621 (Div. 1 + Div. 2) (contest 1307), difficulty 800-3300. 4/7 solutions verified against sample I/O.

7 items

Codeforces Round 621 (Div. 1 + Div. 2)

Div. 1+2 | 7 problems | 4/7 verified | Difficulty 800-3300 | 36m 29s

# Problem Rating Tags Accepted Time ✓
A A 800 greedy, implementation 15,626 3m 1s ✓
B Cow and Friend 1300 geometry, greedy, math 13,855 1m 55s ✓
C Cow and Message 1500 brute-force, dp, math 12,591 13m 13s ✓
D Cow and Fields 1900 binary-search, data-structures, dfs-and-similar 7,169 1m 16s ✓
E Cow and Treats 2500 binary-search, combinatorics, dp 1,363 2m 50s
F Cow and Vacation 3300 dfs-and-similar, dsu, trees 675 3m 17s
G Cow and Exercise 3100 flows, graphs, shortest-paths 597 10m 57s
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greedy implementation Jun 14, 2026
Practice › Codeforces Solutions › Codeforces Round 621 (Div. 1 + Div. 2) ›

CF 1307F - Cow and Vacation

We are working on a tree of cities connected by roads, where every pair of cities is reachable through a unique simple path. Some of these cities contain rest stops.
codeforces competitive-programming dfs-and-similar dsu trees Jun 18, 2026
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CF 1307G - Cow and Exercise

We are given a directed weighted graph with up to 50 vertices, representing fields connected by roads. A cow starts at node 1 and wants to reach node n, and the time it takes is determined by the shortest path in this graph. Now the twist: we are allowed to “slow down” edges.
codeforces competitive-programming flows graphs shortest-paths Jun 16, 2026
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CF 1307B - Cow and Friend

A rabbit starts at the origin in the plane and wants to land exactly at the point $(x, 0)$. He moves by making a sequence of jumps, and each jump can have any direction, but its length must match one of the allowed values given in the input.
codeforces competitive-programming geometry greedy math Jun 16, 2026
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CF 1307D - Cow and Fields

We are given an undirected, connected graph representing fields connected by roads. A traveler starts at node 1 and wants to reach node n using the shortest possible route.
codeforces competitive-programming binary-search data-structures dfs-and-similar graphs greedy shortest-paths sortings Jun 16, 2026
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CF 1307C - Cow and Message

We are given a string of lowercase English letters. A message is any subsequence whose chosen indices form an arithmetic progression. The progression can have any positive difference, including the special case of length one. The task is not to find the message itself.
codeforces competitive-programming brute-force dp math strings Jun 11, 2026
Practice › Codeforces Solutions › Codeforces Round 621 (Div. 1 + Div. 2) ›

CF 1307E - Cow and Treats

Yes, the inequality $nu(n) le 2^{l(n) - lambda(n)}$ holds for all positive integers $n$. Consider an addition chain of minimal length $l(n)$ and let $lambda(n)$ be the length of a shortest chain consisting only of doubling steps.
codeforces competitive-programming binary-search combinatorics dp greedy implementation math Jun 11, 2026