Codeforces Round 954 (Div. 3)

Solutions for Codeforces Round 954 (Div. 3) (contest 1986). 3/8 problems verified against sample I/O. Difficulty range: 800-2500.

8 items

Codeforces Round 954 (Div. 3)

Type: Div. 3 | Problems: 8 | Verified: 3/8 | Rating range: 800-2500 | Time: 16m 3s

Problem	Name	Rating	Tags	Solve Time	Verified
A	X Axis	800	brute-force, geometry, math	1m 36s	✓
B	Matrix Stabilization	1000	brute-force, data-structures, greedy	2m 30s	✗
C	Update Queries	1100	data-structures, greedy, sortings	1m 17s	✓
D	Mathematical Problem	1400	brute-force, dp, greedy	2m 18s	✗
E	Beautiful Array	1700	greedy, math, number-theory	1m 41s	✗
F	Non-academic Problem	1900	dfs-and-similar, graphs, trees	1m 12s	✓
G1	Permutation Problem (Simple Version)	2200	binary-search, brute-force, combinatorics	2m 18s	✗
G2	Permutation Problem (Hard Version)	2500	brute-force, data-structures, hashing	3m 11s	✗

Practice › Codeforces Solutions › Codeforces Round 954 (Div. 3) ›

CF 1986G2 - Permutation Problem (Hard Version)

We are given a permutation of integers from 1 to $n$, and we are asked to count how many pairs of indices $(i, j)$ satisfy $i < j$ and $pi cdot pj$ divisible by $i cdot j$.

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CF 1986G1 - Permutation Problem (Simple Version)

We are given a permutation of length $n$, meaning every number from $1$ to $n$ appears exactly once, but in some shuffled order.

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CF 1986F - Non-academic Problem

We are given a connected undirected graph. Between any two vertices, we can ask whether there is a path connecting them. If a path exists, that pair contributes to the final answer.

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CF 1986D - Mathematical Problem

We are given a string of digits, and our goal is to insert exactly $n-2$ arithmetic symbols, either plus or multiplication, between digits to form a valid arithmetic expression.

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CF 1986E - Beautiful Array

We are given an integer array and a fixed increment value $k$. We are allowed to reorder the array arbitrarily before doing anything else, and then repeatedly apply an operation that increases a single chosen element by exactly $k$.

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CF 1986B - Matrix Stabilization

The problem asks us to stabilize a matrix by repeatedly decreasing “peaks,” which are cells strictly larger than all their neighbors. The matrix is given as an $n times m$ grid of integers.

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CF 1986A - X Axis

We are given three integer points on a one-dimensional number line, specifically the X axis. The task is to find a single integer coordinate such that the sum of the distances from this chosen point to the three given points is minimized.

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CF 1986C - Update Queries

We are given a starting string and a multiset of update operations. Each update consists of a position in the string and a lowercase letter.