Codeforces Round 457 (Div. 2)

Solutions for Codeforces Round 457 (Div. 2) (contest 916). 3/5 problems verified against sample I/O. Difficulty range: 900-2400.

5 items

Codeforces Round 457 (Div. 2)

Type: Div. 2 | Problems: 5 | Verified: 3/5 | Rating range: 900-2400 | Time: 21m 30s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Jamie and Alarm Snooze	900	brute-force, implementation, math	3m 14s	✓
B	Jamie and Binary Sequence (changed after round)	2000	bitmasks, greedy, math	2m 14s	✓
C	Jamie and Interesting Graph	1600	constructive-algorithms, graphs, shortest-paths	5m 35s	✗
D	Jamie and To-do List	2200	data-structures, interactive, trees	4m 6s	✓
E	Jamie and Tree	2400	data-structures, trees	6m 21s	✗

Practice › Codeforces Solutions › Codeforces Round 457 (Div. 2) ›

CF 916E - Jamie and Tree

We are given a tree with values on its vertices, and we need to support three kinds of operations under a changing notion of what “subtree” means. The tree is rooted, but the root is not fixed. Whenever the root changes, the definition of subtree changes accordingly.

Practice › Codeforces Solutions › Codeforces Round 457 (Div. 2) ›

CF 916C - Jamie and Interesting Graph

We are asked to construct an undirected weighted graph with exactly n vertices and m edges that satisfies two prime-related constraints. First, the length of the shortest path from vertex 1 to vertex n must be prime.

Practice › Codeforces Solutions › Codeforces Round 457 (Div. 2) ›

CF 916D - Jamie and To-do List

The system maintains a dynamic collection of named tasks. Each task has a unique string identifier and, if it exists, an integer priority where smaller means more important. Over time, tasks are added, removed, or have their priorities changed.

Practice › Codeforces Solutions › Codeforces Round 457 (Div. 2) ›

CF 916A - Jamie and Alarm Snooze

We are given a wake-up time on a 24-hour clock and a fixed interval x in minutes. Jamie sets an alarm some unknown amount of time before the wake-up moment. After the alarm rings, he repeatedly snoozes it every x minutes until the wake-up time is reached exactly.

Practice › Codeforces Solutions › Codeforces Round 457 (Div. 2) ›

CF 916B - Jamie and Binary Sequence (changed after round)

We want to represent a positive integer n as a sum of exactly k powers of two: $$n = 2^{a1} + 2^{a2} + cdots + 2^{ak}$$ The exponents may be positive, zero, or even negative. Among all valid sequences of length k, we first minimize the largest exponent that appears.