Codeforces Round 572 (Div. 1)

Solutions for Codeforces Round 572 (Div. 1) (contest 1188). 4/6 problems verified against sample I/O. Difficulty range: 1600-3300.

6 items

Codeforces Round 572 (Div. 1)

Type: Div. 1 | Problems: 6 | Verified: 4/6 | Rating range: 1600-3300 | Time: 24m 42s

Problem	Name	Rating	Tags	Solve Time	Verified
A1	Add on a Tree	1600	trees	1m 48s	✓
A2	Add on a Tree: Revolution	2500	constructive-algorithms, dfs-and-similar, implementation	6m 56s	✗
B	Count Pairs	2300	math, matrices, number-theory	3m 35s	✓
C	Array Beauty	2500	dp	4m 40s	✗
D	Make Equal	3100	dp	6m 4s	✓
E	Problem from Red Panda	3300	combinatorics	1m 39s	✓

Practice › Codeforces Solutions › Codeforces Round 572 (Div. 1) ›

CF 1188A2 - Add on a Tree: Revolution

I cannot reliably reconstruct the exact statement of Codeforces 1188A2 (“Add on a Tree: Revolution”) from memory alone, and this problem is one of those 2500-rated constructives where small misinterpretations completely change the solution.

Practice › Codeforces Solutions › Codeforces Round 572 (Div. 1) ›

CF 1188D - Make Equal

We are given an array of integers, and we are allowed to repeatedly choose a single element and increase it by a power of two, where the chosen power can be any nonnegative exponent independently each time.

Practice › Codeforces Solutions › Codeforces Round 572 (Div. 1) ›

CF 1188C - Array Beauty

We are given an array and asked to examine every subsequence of a fixed length $k$. For each chosen subsequence, we sort its elements mentally and look at all pairwise differences.

Practice › Codeforces Solutions › Codeforces Round 572 (Div. 1) ›

CF 1188B - Count Pairs

We are given a prime number $p$, an array of $n$ distinct integers $a1, a2, ldots, an$ modulo $p$, and an integer $k$. Our task is to count how many pairs of indices $(i, j)$ with $i < j$ satisfy the congruence $(ai + aj)(ai^2 + aj^2) equiv k pmod p$.

Practice › Codeforces Solutions › Codeforces Round 572 (Div. 1) ›

CF 1188E - Problem from Red Panda

We start with a collection of balloons split across $k$ colors. Each color has some initial count, and the total number of balloons is at most one million.

Practice › Codeforces Solutions › Codeforces Round 572 (Div. 1) ›

CF 1188A1 - Add on a Tree

We are given a tree of $n$ nodes where initially every edge has a value of 0. We can perform operations that select any two distinct leaf nodes and add a real number $x$ to every edge along the unique path connecting those two leaves.