Codeforces Round 937 (Div. 4)

Solutions for Codeforces Round 937 (Div. 4) (contest 1950). 6/7 problems verified against sample I/O. Difficulty range: 800-1900.

7 items

Codeforces Round 937 (Div. 4)

Type: Div. 4 | Problems: 7 | Verified: 6/7 | Rating range: 800-1900 | Time: 7m 41s

Problem Name Rating Tags Solve Time Verified
A Stair, Peak, or Neither? 800 implementation 1m 4s ✓
B Upscaling 800 implementation 45s ✓
C Clock Conversion 800 implementation, math 51s ✓
D Product of Binary Decimals 1100 brute-force, dp, implementation 1m 17s ✓
E Nearly Shortest Repeating Substring 1500 brute-force, implementation, number-theory 1m 22s ✓
F 0, 1, 2, Tree! 1700 bitmasks, brute-force, greedy 1m ✗
G Shuffling Songs 1900 bitmasks, dfs-and-similar, dp 1m 22s ✓
Practice › Codeforces Solutions › Codeforces Round 937 (Div. 4) ›

CF 1950A - Stair, Peak, or Neither?

We are given three digits, a, b, and c, and must classify their relationship. A sequence is called a stair when the values strictly increase from left to right, meaning a < b < c.
codeforces competitive-programming implementation May 31, 2026
Practice › Codeforces Solutions › Codeforces Round 937 (Div. 4) ›

CF 1950B - Upscaling

We are asked to generate a checkerboard pattern that is made of larger $2 times 2$ tiles. Each tile is either fully filled with the character or fully filled with .. The size of the grid is determined by an input integer $n$, and the final grid has dimensions $2n times 2n.
codeforces competitive-programming implementation May 31, 2026
Practice › Codeforces Solutions › Codeforces Round 937 (Div. 4) ›

CF 1950C - Clock Conversion

We are given times expressed in the 24-hour clock format, for example 00:00 for midnight, 13:45 for one forty-five in the afternoon, or 23:59 for one minute before midnight. Our task is to convert each time into the 12-hour clock format, which uses the familiar AM and PM labels.
codeforces competitive-programming implementation math May 31, 2026
Practice › Codeforces Solutions › Codeforces Round 937 (Div. 4) ›

CF 1950D - Product of Binary Decimals

We are given up to 50,000 independent queries. For each query, a number n is provided, where 1 ≤ n ≤ 100000. A number is called a binary decimal if every digit in its usual decimal representation is either 0 or 1. Examples include 1, 10, 11, 101, and 1001.
codeforces competitive-programming brute-force dp implementation number-theory May 31, 2026
Practice › Codeforces Solutions › Codeforces Round 937 (Div. 4) ›

CF 1950E - Nearly Shortest Repeating Substring

We are given a string s of length n. We want to find the smallest possible length L such that there exists a pattern string k of length L, repeated exactly n / L times, producing a string c of length n, and c differs from s in at most one position.
codeforces competitive-programming brute-force implementation number-theory strings May 31, 2026
Practice › Codeforces Solutions › Codeforces Round 937 (Div. 4) ›

CF 1950F - 0, 1, 2, Tree!

We are asked to construct a rooted tree with a specific number of vertices having 0, 1, or 2 children. The input gives three numbers: a vertices with 2 children, b vertices with 1 child, and c vertices that are leaves.
codeforces competitive-programming bitmasks brute-force greedy implementation trees May 31, 2026
Practice › Codeforces Solutions › Codeforces Round 937 (Div. 4) ›

CF 1950G - Shuffling Songs

Each song has two attributes, a genre and a writer. After removing some songs, we are allowed to reorder the remaining songs arbitrarily.
codeforces competitive-programming bitmasks dfs-and-similar dp graphs hashing implementation strings May 31, 2026