Codeforces Round 987 (Div. 2)

Solutions for Codeforces Round 987 (Div. 2) (contest 2031). 2/6 problems verified against sample I/O. Difficulty range: 800-2800.

6 items

Codeforces Round 987 (Div. 2)

Type: Div. 2 | Problems: 6 | Verified: 2/6 | Rating range: 800-2800 | Time: 11m 44s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Penchick and Modern Monument	800	constructive-algorithms, dp, greedy	1m 40s	✓
B	Penchick and Satay Sticks	900	brute-force, greedy, sortings	2m	✓
C	Penchick and BBQ Buns	1300	constructive-algorithms, math, number-theory	1m 42s	✗
D	Penchick and Desert Rabbit	1700	binary-search, data-structures, dfs-and-similar	1m 43s	✗
E	Penchick and Chloe's Trees	2100	data-structures, dfs-and-similar, dp	2m 6s	✗
F	Penchick and Even Medians	2800	binary-search, constructive-algorithms, interactive	2m 33s	✗

Practice › Codeforces Solutions › Codeforces Round 987 (Div. 2) ›

CF 2031F - Penchick and Even Medians

The original problem is interactive: there is a hidden permutation, and we must locate the positions of the two middle values, namely $frac n2$ and $frac n2 + 1$, using median queries. For the hack version used in the archive, the interaction is removed.

Practice › Codeforces Solutions › Codeforces Round 987 (Div. 2) ›

CF 2031E - Penchick and Chloe's Trees

The problem gives us a rooted tree constructed by Penchick with n vertices and asks us to determine the minimum depth d of a perfect binary tree that Chloe can construct, so that after performing a sequence of "node removal and child promotion" operations, Chloe’s tree…

Practice › Codeforces Solutions › Codeforces Round 987 (Div. 2) ›

CF 2031D - Penchick and Desert Rabbit

We are given a line of trees, each with a height. A rabbit starts at some position and can move between trees using a very specific rule that depends on both position and height. From a tree at index i, the rabbit can jump in two directions.

Practice › Codeforces Solutions › Codeforces Round 987 (Div. 2) ›

CF 2031B - Penchick and Satay Sticks

We have a permutation of the numbers $1$ through $n$. The target is the sorted permutation $[1,2,dots,n]$. The only allowed operation swaps two neighboring positions when the values differ by exactly $1$. For example, $3$ and $4$ may be swapped, but $3$ and $5$ may not.

Practice › Codeforces Solutions › Codeforces Round 987 (Div. 2) ›

CF 2031C - Penchick and BBQ Buns

We are asked to assign a value to each position in an array of length $n$. These values represent “fillings” placed on buns arranged in a line. The same filling may appear multiple times, but only under two strict rules.

Practice › Codeforces Solutions › Codeforces Round 987 (Div. 2) ›

CF 2031A - Penchick and Modern Monument

The problem presents a monument made of $n$ pillars, each with a height $hi$, where the heights are initially in non-increasing order. Penchick wants to modify the monument so that the pillar heights are in non-decreasing order.