Codeforces Round 646 (Div. 2)

4 problems from Codeforces Round 646 (Div. 2) (contest 1363), difficulty 1200-2100. 2/4 solutions verified against sample I/O.

4 items

Codeforces Round 646 (Div. 2)

Div. 2 | 4 problems | 2/4 verified | Difficulty 1200-2100 | 18m 41s

#	Problem	Rating	Tags	Accepted	Time	✓
A	Odd Selection	1200	brute-force, implementation, math	40,389	2m 14s	✓
C	Game On Leaves	1600	games, trees	21,072	6m 12s	✓
D	Guess The Maximums	2100	binary-search, implementation, interactive	4,413	6m 18s
E	Tree Shuffling	2000	dfs-and-similar, dp, greedy	7,495	3m 57s

Practice › Codeforces Solutions › Codeforces Round 646 (Div. 2) ›

CF 1363D - Guess The Maximums

We are given an array $A$ of length $n$, but we cannot see it directly. Instead, we can ask queries: pick any subset of indices and the judge returns the maximum value of $A$ over those indices. Along with this hidden array, we are given $k$ special index sets $S1, S2, dots, Sk$.

Practice › Codeforces Solutions › Codeforces Round 646 (Div. 2) ›

CF 1363E - Tree Shuffling

We are given a rooted tree where each node carries two bits of information: an initial binary digit and a desired final binary digit.

Practice › Codeforces Solutions › Codeforces Round 646 (Div. 2) ›

CF 1363C - Game On Leaves

The game is played on a tree, which is an undirected, connected, acyclic graph. Each node is numbered from $1$ to $n$, and one node $x$ is special. Two players take turns removing leaf nodes, where a leaf is a node with only one neighbor, along with its connecting edge.

Practice › Codeforces Solutions › Codeforces Round 646 (Div. 2) ›

CF 1363A - Odd Selection

We are given an array of integers and must choose exactly x elements from it. The chosen elements can come from any positions in the array. The question is whether there exists a selection of exactly x elements whose sum is odd.