Codeforces Round 720 (Div. 2)

Solutions for Codeforces Round 720 (Div. 2) (contest 1521). 0/5 problems verified against sample I/O. Difficulty range: 1000-2700.

5 items

Codeforces Round 720 (Div. 2)

Type: Div. 2 | Problems: 5 | Verified: 0/5 | Rating range: 1000-2700 | Time: 26m 47s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Nastia and Nearly Good Numbers	1000	constructive-algorithms, math, number-theory	2m 11s	✗
B	Nastia and a Good Array	1300	constructive-algorithms, math, number-theory	4m 34s	✗
C	Nastia and a Hidden Permutation	2000	constructive-algorithms, interactive	2m 36s	✗
D	Nastia Plays with a Tree	2500	constructive-algorithms, data-structures, dfs-and-similar	14m 56s	✗
E	Nastia and a Beautiful Matrix	2700	binary-search, constructive-algorithms, dp	2m 30s	✗

Practice › Codeforces Solutions › Codeforces Round 720 (Div. 2) ›

CF 1521D - Nastia Plays with a Tree

We start with a tree, meaning a connected graph with $n$ vertices and exactly $n-1$ edges. Each move allows us to remove one existing edge and insert a new edge between any two vertices.

Practice › Codeforces Solutions › Codeforces Round 720 (Div. 2) ›

CF 1521E - Nastia and a Beautiful Matrix

We are given counts of values 1..k. Value i must appear exactly ai times. Empty cells are allowed and are represented by 0. We must place all copies into an n × n matrix and minimize n. Every 2 × 2 submatrix must satisfy two conditions.

Practice › Codeforces Solutions › Codeforces Round 720 (Div. 2) ›

CF 1521B - Nastia and a Good Array

We are given an array of positive integers, and we need to transform it into what Nastia calls a good array. A good array is defined as one where every pair of consecutive elements is coprime.

Practice › Codeforces Solutions › Codeforces Round 720 (Div. 2) ›

CF 1521C - Nastia and a Hidden Permutation

We are asked to reconstruct a hidden permutation of length n containing all integers from 1 to n using an interactive querying mechanism. For each query, we choose two distinct indices i and j, a type t (either 1 or 2), and a threshold x.

Practice › Codeforces Solutions › Codeforces Round 720 (Div. 2) ›

CF 1521A - Nastia and Nearly Good Numbers

A radix conversion routine transforms a nonnegative integer written in one base into its representation in another base. The program under discussion is Method 1a from Section 4.