Codeforces Round 909 (Div. 3)

Solutions for Codeforces Round 909 (Div. 3) (contest 1899). 5/7 problems verified against sample I/O. Difficulty range: 800-1900.

7 items

Codeforces Round 909 (Div. 3)

Type: Div. 3 | Problems: 7 | Verified: 5/7 | Rating range: 800-1900 | Time: 12m 9s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Game with Integers	800	games, math, number-theory	1m 31s	✓
B	250 Thousand Tons of TNT	1100	brute-force, implementation, number-theory	2m 22s	✓
C	Yarik and Array	1100	dp, greedy, two-pointers	1m 37s	✓
D	Yarik and Musical Notes	1300	hashing, math, number-theory	1m 41s	✓
E	Queue Sort	1300	greedy, implementation, sortings	2m 12s	✓
F	Alex's whims	1600	constructive-algorithms, graphs, greedy	2m	✗
G	Unusual Entertainment	1900	data-structures, dfs-and-similar, dsu	46s	✗

Practice › Codeforces Solutions › Codeforces Round 909 (Div. 3) ›

CF 1899F - Alex's whims

We are given a tree with $n$ nodes, but the tree is not fixed in its usefulness. Over $q$ days, a value $di$ is announced, and each day we must ensure that the current tree contains at least one pair of leaves whose distance is exactly $di$.

Practice › Codeforces Solutions › Codeforces Round 909 (Div. 3) ›

CF 1899G - Unusual Entertainment

We have a rooted tree with root at vertex 1. A permutation p contains every vertex exactly once. Each query gives three values (l, r, x). We look at the vertices appearing in the permutation segment p[l...

Practice › Codeforces Solutions › Codeforces Round 909 (Div. 3) ›

CF 1899E - Queue Sort

We are given an array of integers, and we want to sort it in non-decreasing order. The catch is that we cannot arbitrarily swap elements.

Practice › Codeforces Solutions › Codeforces Round 909 (Div. 3) ›

CF 1899D - Yarik and Musical Notes

We are given a sequence of integers a1, a2, ..., an, where each integer represents the exponent of 2 forming a musical note: bi = 2^{ai}. Yarik defines a combination of two notes (bi, bj) as bi^{bj}.

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CF 1899B - 250 Thousand Tons of TNT

The problem asks us to find the maximum possible weight difference between two trucks when loading boxes of TNT. We have a row of boxes with given weights, and we can choose any truck size $k$ from 1 to $n$ as long as it divides $n$.

Practice › Codeforces Solutions › Codeforces Round 909 (Div. 3) ›

CF 1899C - Yarik and Array

We are given several independent test cases. Each test case provides an integer array, and the task is to choose a non-empty contiguous segment whose sum is as large as possible, under one additional restriction: adjacent elements inside the chosen segment must alternate in…

Practice › Codeforces Solutions › Codeforces Round 909 (Div. 3) ›

CF 1899A - Game with Integers

We are asked to analyze a simple two-player game with integers. The game starts with a number $n$. Vanya moves first, and each player can either increment or decrement the number by 1 on their turn. Vanya wins immediately if, after his move, the number becomes divisible by 3.