Codeforces Round 236 (Div. 2)

5 problems from Codeforces Round 236 (Div. 2) (contest 402), difficulty 1100-2200. 5/5 solutions verified against sample I/O.

5 items

Codeforces Round 236 (Div. 2)

Div. 2 | 5 problems | 5/5 verified | Difficulty 1100-2200 | 18m 53s

# Problem Rating Tags Accepted Time ✓
A Nuts 1100 greedy, math 4,879 4m 26s ✓
B Trees in a Row 1400 brute-force, implementation 3,993 4m 25s ✓
C Searching for Graph 1500 brute-force, constructive-algorithms, graphs 6,367 4m 51s ✓
D Upgrading Array 1800 dp, greedy, math 2,787 1m 3s ✓
E Strictly Positive Matrix 2200 graphs, math 2,329 4m 8s ✓
Practice › Codeforces Solutions › Codeforces Round 236 (Div. 2) ›

CF 402E - Strictly Positive Matrix

We are given a square matrix $a$ of size $n times n$ whose elements are all non-negative integers. The matrix can be thought of as a weighted adjacency matrix of a graph with $n$ nodes, where $a{ij} 0$ indicates a direct edge from node $i$ to node $j$.
codeforces competitive-programming graphs math Jun 7, 2026
Practice › Codeforces Solutions › Codeforces Round 236 (Div. 2) ›

CF 402C - Searching for Graph

We are asked to construct a special type of undirected graph. The graph has n vertices and a parameter p, and it must satisfy two global conditions. First, the total number of edges is exactly 2n + p. Second, no subgraph of k vertices may have more than 2k + p edges.
codeforces competitive-programming brute-force constructive-algorithms graphs Jun 7, 2026
Practice › Codeforces Solutions › Codeforces Round 236 (Div. 2) ›

CF 402A - Nuts

We are asked to distribute a given number of nuts into boxes, but the boxes are not simple containers. Each box can be split into sections using “divisors,” and every section can hold at most a certain number of nuts.
codeforces competitive-programming greedy math Jun 7, 2026
Practice › Codeforces Solutions › Codeforces Round 236 (Div. 2) ›

CF 402B - Trees in a Row

We have a row of trees, each with a given height. The Queen wants the trees arranged in perfect arithmetic progression: the difference between consecutive tree heights must be exactly $k$.
codeforces competitive-programming brute-force implementation Jun 7, 2026
Practice › Codeforces Solutions › Codeforces Round 236 (Div. 2) ›

CF 402D - Upgrading Array

We are given an array of positive integers and a set of "bad" prime numbers. Every other prime not in the bad set is implicitly "good." Each number in the array contributes to a total "beauty" score determined by its prime factorization.
codeforces competitive-programming dp greedy math number-theory May 29, 2026