Codeforces Round 768 (Div. 1)

Solutions for Codeforces Round 768 (Div. 1) (contest 1630). 2/6 problems verified against sample I/O. Difficulty range: 1500-3400.

6 items

Codeforces Round 768 (Div. 1)

Type: Div. 1 | Problems: 6 | Verified: 2/6 | Rating range: 1500-3400 | Time: 13m 30s

Problem Name Rating Tags Solve Time Verified
A And Matching 1500 bitmasks, constructive-algorithms 2m 33s ✗
B Range and Partition 1800 binary-search, constructive-algorithms, data-structures 3m 26s ✗
C Paint the Middle 2200 dp, greedy, sortings 1m 33s ✓
D Flipping Range 2400 constructive-algorithms, dp, greedy 1m 47s ✓
E Expected Components 2900 combinatorics, math, number-theory 2m 32s ✗
F Making It Bipartite 3400 flows, graph-matchings, graphs 1m 39s ✗
Practice › Codeforces Solutions › Codeforces Round 768 (Div. 1) ›

CF 1630E - Expected Components

This problem is rated 3500 and its solution relies on a fairly deep structural characterization of graphs whose cycle space admits a consistent cyclic orientation.
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Practice › Codeforces Solutions › Codeforces Round 768 (Div. 1) ›

CF 1630F - Making It Bipartite

We are given a set of distinct integers, each representing a vertex. We build an undirected graph where two vertices are connected whenever one value divides the other. The task is to remove as few vertices as possible so that the remaining graph becomes bipartite.
codeforces competitive-programming flows graph-matchings graphs number-theory Jun 10, 2026
Practice › Codeforces Solutions › Codeforces Round 768 (Div. 1) ›

CF 1630B - Range and Partition

We are given an array of integers, and the task is to find a numeric range [x, y] and split the array into exactly k contiguous subarrays so that in each subarray, more than half of the elements fall inside the chosen range. The goal is to minimize the width of the range, y - x.
codeforces competitive-programming binary-search constructive-algorithms data-structures greedy two-pointers Jun 10, 2026
Practice › Codeforces Solutions › Codeforces Round 768 (Div. 1) ›

CF 1630D - Flipping Range

We are given an array of integers, and a set of allowed segment lengths. For each length in this set, we can pick any contiguous subarray of that size and flip the sign of every element in it.
codeforces competitive-programming constructive-algorithms dp greedy number-theory Jun 10, 2026
Practice › Codeforces Solutions › Codeforces Round 768 (Div. 1) ›

CF 1630A - And Matching

This problem is rated 3500 and its solution relies on a fairly deep structural characterization of graphs whose cycle space admits a consistent cyclic orientation.
codeforces competitive-programming bitmasks constructive-algorithms Jun 10, 2026
Practice › Codeforces Solutions › Codeforces Round 768 (Div. 1) ›

CF 1630C - Paint the Middle

We are given a sequence of numbers, each initially unpainted. The only operation allowed is to pick three elements $i < j < k$ such that the outer two elements have equal values and all three elements are unpainted, then paint the middle element.
codeforces competitive-programming dp greedy sortings two-pointers Jun 10, 2026