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

5 problems from Codeforces Round 621 (Div. 1 + Div. 2) (contest 1307), difficulty 1300-3100. 3/5 solutions verified against sample I/O.

5 items

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

Div. 1+2 | 5 problems | 3/5 verified | Difficulty 1300-3100 | 30m 11s

#	Problem	Rating	Tags	Accepted	Time	✓
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
G	Cow and Exercise	3100	flows, graphs, shortest-paths	597	10m 57s

Practice › Codeforces Solutions › Codeforces Round 621 (Div. 1 + Div. 2) ›

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.

Practice › Codeforces Solutions › Codeforces Round 621 (Div. 1 + Div. 2) ›

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.

Practice › Codeforces Solutions › Codeforces Round 621 (Div. 1 + Div. 2) ›

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.

Practice › Codeforces Solutions › Codeforces Round 621 (Div. 1 + Div. 2) ›

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.

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.