Codeforces Round 1000 (Div. 2)

7 problems from Codeforces Round 1000 (Div. 2) (contest 2063), difficulty 800-2700. 2/7 solutions verified against sample I/O.

7 items

Codeforces Round 1000 (Div. 2)

Div. 2 | 7 problems | 2/7 verified | Difficulty 800-2700 | 13m 8s

#	Problem	Rating	Tags	Accepted	Time	✓
A	Minimal Coprime	800	math, number-theory	31,755	1m 50s	✓
B	Subsequence Update	1100	constructive-algorithms, data-structures, greedy	23,189	1m 26s	✓
C	Remove Exactly Two	1600	brute-force, data-structures, dfs-and-similar	14,637	1m 53s
D	Game With Triangles	2000	binary-search, brute-force, data-structures	5,040	1m 46s
E	Triangle Tree	2300	data-structures, dfs-and-similar, dp	2,386	2m 35s
F1	Counting Is Not Fun (Easy Version)	2400	combinatorics, data-structures, dfs-and-similar	1,549	1m 55s
F2	Counting Is Not Fun (Hard Version)	2700	combinatorics, data-structures, dfs-and-similar	928	1m 43s

Practice › Codeforces Solutions › Codeforces Round 1000 (Div. 2) ›

CF 2063F2 - Counting Is Not Fun (Hard Version)

We are given a hidden balanced bracket sequence of length $2n$. The structure of the sequence is not arbitrary: it can be fully described by a set of $n$ disjoint “matching events”, where each event connects an opening bracket at position $l$ with a closing bracket at…

Practice › Codeforces Solutions › Codeforces Round 1000 (Div. 2) ›

CF 2063E - Triangle Tree

We are given a rooted tree with root at vertex 1. For every unordered pair of vertices (u, v), we only care about pairs where neither vertex is an ancestor of the other.

Practice › Codeforces Solutions › Codeforces Round 1000 (Div. 2) ›

CF 2063F1 - Counting Is Not Fun (Easy Version)

The problem asks us to count balanced bracket sequences under incremental constraints. We are given a balanced sequence of 2n brackets, but we do not know its content.

Practice › Codeforces Solutions › Codeforces Round 1000 (Div. 2) ›

CF 2063D - Game With Triangles

We are given two horizontal layers of points. One layer lies on the line $y=0$, the other lies on $y=2$. Each layer contains distinct x-coordinates.

Practice › Codeforces Solutions › Codeforces Round 1000 (Div. 2) ›

CF 2063C - Remove Exactly Two

The problem asks us to consider a tree of n vertices and determine the maximum number of connected components that can result after removing exactly two vertices.

Practice › Codeforces Solutions › Codeforces Round 1000 (Div. 2) ›

CF 2063A - Minimal Coprime

We are given an integer segment $[l,r]$. A segment $[a,b]$ is called coprime when the two endpoints $a$ and $b$ have greatest common divisor equal to $1$. Among all coprime segments, we only care about those that are minimal.

Practice › Codeforces Solutions › Codeforces Round 1000 (Div. 2) ›

CF 2063B - Subsequence Update

We are given an array and a target segment $[l, r]$. We compute the sum of elements inside this segment, but we are allowed to perform exactly one global operation before measuring it. The operation is not a standard reversal of a subarray.