Codeforces Round 875 (Div. 1)

Solutions for Codeforces Round 875 (Div. 1) (contest 1830). 0/4 problems verified against sample I/O. Difficulty range: 1400-3500.

4 items

Codeforces Round 875 (Div. 1)

Type: Div. 1 | Problems: 4 | Verified: 0/4 | Rating range: 1400-3500 | Time: 6m 15s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Copil Copac Draws Trees	1400	dfs-and-similar, dp, graphs	1m 29s	✗
B	The BOSS Can Count Pairs	2000	brute-force, math	2m 10s	✗
D	Mex Tree	2800	brute-force, dp, trees	1m 22s	✗
E	Bully Sort	3500	data-structures, math	1m 14s	✗

Practice › Codeforces Solutions › Codeforces Round 875 (Div. 1) ›

CF 1830E - Bully Sort

We are given a permutation of length $n$, which is an array containing each number from $1$ to $n$ exactly once. A "bully swap" is defined as picking the largest number that is not in its sorted position and swapping it with the smallest number to its right.

Practice › Codeforces Solutions › Codeforces Round 875 (Div. 1) ›

CF 1830D - Mex Tree

We are given a tree where every vertex can be assigned one of two labels, either 0 or 1. Once we choose a labeling, we consider every pair of vertices $(u, v)$, including the case $u = v$.

Practice › Codeforces Solutions › Codeforces Round 875 (Div. 1) ›

CF 1830B - The BOSS Can Count Pairs

The solution correctly generalizes the serial test from pairs to $k$-tuples by grouping the sequence into disjoint blocks of length $k$, ensuring independence under the null hypothesis.

Practice › Codeforces Solutions › Codeforces Round 875 (Div. 1) ›

CF 1830A - Copil Copac Draws Trees

We are given a tree with $n$ vertices described by $n-1$ edges. Copil Copac draws this tree in discrete steps, starting from vertex 1. At each step, he iterates through the list of edges in the order they are given.