Codeforces Round 788 (Div. 2)

Solutions for Codeforces Round 788 (Div. 2) (contest 1670). 1/6 problems verified against sample I/O. Difficulty range: 800-2400.

6 items

Codeforces Round 788 (Div. 2)

Type: Div. 2 | Problems: 6 | Verified: 1/6 | Rating range: 800-2400 | Time: 21m 14s

Problem Name Rating Tags Solve Time Verified
A Prof. Slim 800 greedy, implementation, sortings 1m 58s ✓
B Dorms War 1100 brute-force, implementation, strings 45s ✗
C Where is the Pizza? 1400 data-structures, dfs-and-similar, dsu 12m 12s ✗
D Very Suspicious 1700 binary-search, brute-force, geometry 1m 56s ✗
E Hemose on the Tree 2200 bitmasks, constructive-algorithms, dfs-and-similar 3m 34s ✗
F Jee, You See? 2400 bitmasks, combinatorics, dp 49s ✗
Practice › Codeforces Solutions › Codeforces Round 788 (Div. 2) ›

CF 1670C - Where is the Pizza?

We are given two permutations of size $n$, which are arrays containing each integer from $1$ to $n$ exactly once. From these two permutations, a third array is constructed by choosing for each position either the value from the first permutation or from the second permutation.
codeforces competitive-programming data-structures dfs-and-similar dsu graphs implementation math Jun 10, 2026
Practice › Codeforces Solutions › Codeforces Round 788 (Div. 2) ›

CF 1670E - Hemose on the Tree

We are given a tree with $n = 2^p$ vertices. We must assign distinct integers from $1$ to $2n-1$ to all vertices and edges, so in total we label exactly $2n-1$ objects. After fixing these labels, we also choose a root.
codeforces competitive-programming bitmasks constructive-algorithms dfs-and-similar trees Jun 10, 2026
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CF 1670F - Jee, You See?

Working
codeforces competitive-programming bitmasks combinatorics dp Jun 10, 2026
Practice › Codeforces Solutions › Codeforces Round 788 (Div. 2) ›

CF 1670D - Very Suspicious

We are working with an infinite hexagonal grid, where each hexagon shares edges with six neighbors. The task is to add straight lines along the directions of the hexagon edges to form equilateral triangles.
codeforces competitive-programming binary-search brute-force geometry greedy implementation math Jun 10, 2026
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CF 1670A - Prof. Slim

We are given an array of non-zero integers, and we are allowed to repeatedly swap the signs of any two elements that have opposite signs. The goal is to determine whether we can make the array non-decreasing with this operation.
codeforces competitive-programming greedy implementation sortings Jun 10, 2026
Practice › Codeforces Solutions › Codeforces Round 788 (Div. 2) ›

CF 1670B - Dorms War

We are given a string that represents a password and a set of special characters. A transformation program can be applied repeatedly to the string.
codeforces competitive-programming brute-force implementation strings Jun 10, 2026