Codeforces Round 881 (Div. 3)

Solutions for Codeforces Round 881 (Div. 3) (contest 1843). 6/7 problems verified against sample I/O. Difficulty range: 800-2300.

7 items

Codeforces Round 881 (Div. 3)

Type: Div. 3 | Problems: 7 | Verified: 6/7 | Rating range: 800-2300 | Time: 15m 1s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Sasha and Array Coloring	800	greedy, sortings, two-pointers	1m 43s	✓
B	Long Long	800	greedy, math, two-pointers	4m 50s	✗
C	Sum in Binary Tree	800	bitmasks, combinatorics, math	1m 27s	✓
D	Apple Tree	1200	combinatorics, dfs-and-similar, dp	2m 56s	✓
E	Tracking Segments	1600	binary-search, brute-force, data-structures	1m 47s	✓
F1	Omsk Metro (simple version)	1800	data-structures, dfs-and-similar, dp	1m 11s	✓
F2	Omsk Metro (hard version)	2300	data-structures, dfs-and-similar, divide-and-conquer	1m 7s	✓

Practice › Codeforces Solutions › Codeforces Round 881 (Div. 3) ›

CF 1843F2 - Omsk Metro (hard version)

The problem models a growing tree structure representing the Omsk metro system. Each node in the tree is a station, starting with station 1 with weight +1. New stations are added one by one, each connected to an existing station, and each having a weight of either +1 or -1.

Practice › Codeforces Solutions › Codeforces Round 881 (Div. 3) ›

CF 1843B - Long Long

The problem here is entirely structural, not algorithmic. Your test harness calls solve(), but in the code you ran, solve was never defined in the same script.

Practice › Codeforces Solutions › Codeforces Round 881 (Div. 3) ›

CF 1843F1 - Omsk Metro (simple version)

We are given a growing tree, representing the Omsk metro, where each station has a weight of either 1 or -1. The tree initially has a single station numbered 1 with weight 1.

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CF 1843D - Apple Tree

We are given a rooted tree with n vertices, rooted at vertex 1. Each vertex may have zero or more children. Two apples are placed on arbitrary vertices x and y. When the tree is shaken, each apple moves down to a child at every step until it reaches a leaf, where it falls.

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CF 1843E - Tracking Segments

We start with an array of length n filled entirely with zeros. There are m segments. A segment is considered beautiful when the number of ones inside it is strictly greater than the number of zeros inside the same segment.

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CF 1843A - Sasha and Array Coloring

We are given an array of integers. Every element must be assigned to exactly one color, and we may use any number of colors. For each color, we look at all values assigned to that color.

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CF 1843C - Sum in Binary Tree

The problem describes an infinite complete binary tree where nodes are numbered sequentially layer by layer. The root has number 1, its left child is 2, right child is 3, and the pattern continues such that each node gets two children with the next available numbers.