Codeforces Round 915 (Div. 2)

Solutions for Codeforces Round 915 (Div. 2) (contest 1905). 5/6 problems verified against sample I/O. Difficulty range: 800-2600.

6 items

Codeforces Round 915 (Div. 2)

Type: Div. 2 | Problems: 6 | Verified: 5/6 | Rating range: 800-2600 | Time: 11m 25s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Constructive Problems	800	constructive-algorithms, math	1m 43s	✓
B	Begginer's Zelda	1100	greedy, trees	1m 50s	✓
C	Largest Subsequence	1400	greedy, strings	3m 25s	✗
D	Cyclic MEX	2000	data-structures, implementation, math	1m 23s	✓
E	One-X	2400	combinatorics, dfs-and-similar, dp	1m 20s	✓
F	Field Should Not Be Empty	2600	brute-force, data-structures, divide-and-conquer	1m 44s	✓

Practice › Codeforces Solutions › Codeforces Round 915 (Div. 2) ›

CF 1905C - Largest Subsequence

We are given a string of lowercase English letters, and our goal is to transform it into a non-decreasing sorted string using a specific operation.

Practice › Codeforces Solutions › Codeforces Round 915 (Div. 2) ›

CF 1905E - One-X

We are asked to work with a segment tree built over an array of length $n$, where the segment tree is the standard binary recursive construction. Each node of the tree corresponds to a segment of the array, and the root node is labeled $1$.

Practice › Codeforces Solutions › Codeforces Round 915 (Div. 2) ›

CF 1905B - Begginer's Zelda

We are given a tree and a special operation. In one operation, we choose any two vertices and look at the unique path between them. Every vertex on that path is merged into a single new vertex.

Practice › Codeforces Solutions › Codeforces Round 915 (Div. 2) ›

CF 1905D - Cyclic MEX

We are given a permutation of numbers from 0 to n−1. We are allowed to rotate this array cyclically, and for each possible rotation we compute a score as we scan from left to right.

Practice › Codeforces Solutions › Codeforces Round 915 (Div. 2) ›

CF 1905F - Field Should Not Be Empty

We are given a permutation of numbers from 1 to $n$. The task revolves around identifying "good" positions in the array. A position is called good if all elements to its left are smaller and all elements to its right are larger.

Practice › Codeforces Solutions › Codeforces Round 915 (Div. 2) ›

CF 1905A - Constructive Problems

We are given a rectangular grid representing the cities of Gridlandia. Every city starts collapsed. The government can choose to rebuild some cities directly.