Pinely Round 4 (Div. 1 + Div. 2)

Solutions for Pinely Round 4 (Div. 1 + Div. 2) (contest 1991). 1/9 problems verified against sample I/O. Difficulty range: 800-3500.

9 items

Pinely Round 4 (Div. 1 + Div. 2)

Type: Div. 1+2 | Problems: 9 | Verified: 1/9 | Rating range: 800-3500 | Time: 24m 17s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Maximize the Last Element	800	greedy, implementation	1m 35s	✗
B	AND Reconstruction	1100	bitmasks, constructive-algorithms, greedy	3m 1s	✗
C	Absolute Zero	1300	constructive-algorithms, greedy, math	3m 20s	✗
D	Prime XOR Coloring	1900	bitmasks, constructive-algorithms, graphs	1m 29s	✓
E	Coloring Game	1900	constructive-algorithms, dfs-and-similar, games	3m 7s	✗
F	Triangle Formation	2200	brute-force, greedy, implementation	3m 11s	✗
G	Grid Reset	2700	constructive-algorithms, greedy, implementation	3m 38s	✗
H	Prime Split Game	3300	bitmasks, dp, fft	2m 11s	✗
I	Grid Game	3500	constructive-algorithms, games, graph-matchings	2m 45s	✗

Practice › Codeforces Solutions › Pinely Round 4 (Div. 1 + Div. 2) ›

CF 1991I - Grid Game

We are asked to play an interactive game on a rectangular grid of size $n times m$. Each cell must be filled with a unique integer from $1$ to $n cdot m$. Once the grid is filled, the interactor and we take turns picking unchosen cells.

Practice › Codeforces Solutions › Pinely Round 4 (Div. 1 + Div. 2) ›

CF 1991H - Prime Split Game

In this problem, Alice and Bob are playing a turn-based game with piles of stones. Each pile contains some number of stones, and a player on their turn must choose a number of piles to remove and an equal number of piles to split, where the split must produce piles with prime…

Practice › Codeforces Solutions › Pinely Round 4 (Div. 1 + Div. 2) ›

CF 1991G - Grid Reset

We are asked to manage a dynamic grid coloring process. The grid has $n$ rows and $m$ columns, all initially white. We are given an integer $k$ and a sequence of operations. Each operation is either horizontal or vertical.

Practice › Codeforces Solutions › Pinely Round 4 (Div. 1 + Div. 2) ›

CF 1991F - Triangle Formation

We are given a sequence of sticks, each with a positive integer length. For each query, we are asked whether it is possible to pick exactly six distinct sticks from a given contiguous subarray such that we can form two non-degenerate triangles.

Practice › Codeforces Solutions › Pinely Round 4 (Div. 1 + Div. 2) ›

CF 1991E - Coloring Game

We are asked to play a two-player game on a connected undirected graph where each vertex can be colored with one of three colors. The game proceeds in rounds equal to the number of vertices.

Practice › Codeforces Solutions › Pinely Round 4 (Div. 1 + Div. 2) ›

CF 1991C - Absolute Zero

We are given an array of non-negative integers, and in one operation we can pick any number $x$ and replace every element $ai$ with its absolute difference from $x$, $ The key constraint is the array size $n$ up to $2 cdot 10^5$ and the sum of $n$ across all test cases also…

Practice › Codeforces Solutions › Pinely Round 4 (Div. 1 + Div. 2) ›

CF 1991D - Prime XOR Coloring

We are given a set of vertices labeled from 1 to n. Two vertices are connected if the XOR of their labels is a prime number. The task is to assign a color to every vertex so that no edge connects two vertices of the same color, while using as few colors as possible.

Practice › Codeforces Solutions › Pinely Round 4 (Div. 1 + Div. 2) ›

CF 1991B - AND Reconstruction

We are given an array b of length n-1 and need to construct an array a of length n such that each element of b equals the bitwise AND of consecutive elements of a. In other words, for each i from 1 to n-1, b[i] = a[i] & a[i+1].

Practice › Codeforces Solutions › Pinely Round 4 (Div. 1 + Div. 2) ›

CF 1991A - Maximize the Last Element

We are given an array of odd length, and we repeatedly compress it by deleting two neighboring elements in one move until only one value remains. Each deletion removes a contiguous pair, and everything else shifts together.