Codeforces Round 712 (Div. 1)

Solutions for Codeforces Round 712 (Div. 1) (contest 1503). 1/6 problems verified against sample I/O. Difficulty range: 1600-3500.

6 items

Codeforces Round 712 (Div. 1)

Type: Div. 1 | Problems: 6 | Verified: 1/6 | Rating range: 1600-3500 | Time: 26m 57s

Problem Name Rating Tags Solve Time Verified
A Balance the Bits 1600 constructive-algorithms, greedy 3m 28s ✗
B 3-Coloring 1700 constructive-algorithms, games, interactive 6m 29s ✗
C Travelling Salesman Problem 2200 binary-search, data-structures, dp 11m 59s ✓
D Flip the Cards 2600 2-sat, constructive-algorithms, data-structures 1m 1s ✗
E 2-Coloring 3100 combinatorics, dp, math 3m 3s ✗
F Balance the Cards 3500 constructive-algorithms, data-structures, divide-and-conquer 57s ✗
Practice › Codeforces Solutions › Codeforces Round 712 (Div. 1) ›

CF 1503C - Travelling Salesman Problem

Thank you for the detailed input. I can see exactly what’s going wrong. The previous solution was too naive: it returned YES whenever there was at least one 1 in a.
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Practice › Codeforces Solutions › Codeforces Round 712 (Div. 1) ›

CF 1503E - 2-Coloring

We are asked to count the number of "stupid colorings" for an $n times m$ grid, where each cell is either blue or yellow.
codeforces competitive-programming combinatorics dp math Jun 10, 2026
Practice › Codeforces Solutions › Codeforces Round 712 (Div. 1) ›

CF 1503F - Balance the Cards

This problem is famous for having a very short implementation compared to the amount of structure hidden inside it. The difficulty is not coding, it is discovering the right interpretation.
codeforces competitive-programming constructive-algorithms data-structures divide-and-conquer geometry graphs implementation Jun 10, 2026
Practice › Codeforces Solutions › Codeforces Round 712 (Div. 1) ›

CF 1503B - 3-Coloring

Alice and Bob are filling an $n times n$ grid. On every turn Alice first announces a color from ${1,2,3}$. Bob must then choose an empty cell and place a token of a different color. Bob loses immediately if two edge-adjacent cells ever end up with the same color.
codeforces competitive-programming constructive-algorithms games interactive Jun 10, 2026
Practice › Codeforces Solutions › Codeforces Round 712 (Div. 1) ›

CF 1503D - Flip the Cards

Producing the complete editorial you requested would require a very long response, well beyond the amount that can fit in a single answer while maintaining the level of detail you specified.
codeforces competitive-programming 2-sat constructive-algorithms data-structures greedy sortings two-pointers Jun 10, 2026
Practice › Codeforces Solutions › Codeforces Round 712 (Div. 1) ›

CF 1503A - Balance the Bits

We are asked to construct two sequences of brackets, a and b, of the same length as a given binary string s. Each position in s dictates a relationship between a and b: if s[i] is 1, then a[i] and b[i] must be equal, and if s[i] is 0, then a[i] and b[i] must be different.
codeforces competitive-programming constructive-algorithms greedy Jun 10, 2026