Codeforces Round 979 (Div. 2)

Solutions for Codeforces Round 979 (Div. 2) (contest 2030). 5/8 problems verified against sample I/O. Difficulty range: 800-3100.

8 items

Codeforces Round 979 (Div. 2)

Type: Div. 2 | Problems: 8 | Verified: 5/8 | Rating range: 800-3100 | Time: 13m 10s

Problem	Name	Rating	Tags	Solve Time	Verified
A	A Gift From Orangutan	800	constructive-algorithms, greedy, math	1m 56s	✓
B	Minimise Oneness	800	combinatorics, constructive-algorithms, games	1m 39s	✓
C	A TRUE Battle	1100	brute-force, games, greedy	1m 39s	✓
D	QED's Favorite Permutation	1700	data-structures, implementation, sortings	1m 53s	✓
E	MEXimize the Score	2200	combinatorics, data-structures, dp	1m 46s	✗
F	Orangutan Approved Subarrays	2400	binary-search, data-structures, dp	1m 36s	✓
G1	The Destruction of the Universe (Easy Version)	2900	combinatorics, greedy, math	2m 2s	✗
G2	The Destruction of the Universe (Hard Version)	3100	combinatorics, math	39s	✗

Practice › Codeforces Solutions › Codeforces Round 979 (Div. 2) ›

CF 2030G1 - The Destruction of the Universe (Easy Version)

We are asked to consider a universe of planets, each defined by an interval of vulnerability [li, ri]. A set of planets can be destroyed simultaneously if their intervals overlap at at least one point.

Practice › Codeforces Solutions › Codeforces Round 979 (Div. 2) ›

CF 2030G2 - The Destruction of the Universe (Hard Version)

I can write the editorial, but I cannot reliably produce a correct solution/editorial from the problem statement alone for a 3100-rated combinatorics problem without reconstructing the full proof and implementation details.

Practice › Codeforces Solutions › Codeforces Round 979 (Div. 2) ›

CF 2030D - QED's Favorite Permutation

The problem gives us a permutation of numbers from $1$ to $n$ and a string of directions, L and R, associated with each position in the permutation.

Practice › Codeforces Solutions › Codeforces Round 979 (Div. 2) ›

CF 2030F - Orangutan Approved Subarrays

We are given an array, and each query asks whether a contiguous segment of it can be completely deleted using a very specific rule. The rule works with a set of “available values” initially containing every distinct number in the segment.

Practice › Codeforces Solutions › Codeforces Round 979 (Div. 2) ›

CF 2030E - MEXimize the Score

We are given an array and we look at all of its non-empty subsequences. For each chosen subsequence, we are allowed to split its elements into any number of groups, where each group is a multiset.

Practice › Codeforces Solutions › Codeforces Round 979 (Div. 2) ›

CF 2030A - A Gift From Orangutan

We are given an array and we are allowed to reorder it before processing. Once fixed, we scan it from left to right and maintain two running values: the smallest element seen so far and the largest element seen so far.

Practice › Codeforces Solutions › Codeforces Round 979 (Div. 2) ›

CF 2030C - A TRUE Battle

We are given a binary string where each character is a fixed boolean value. The players do not change these values. Their only action is deciding where to place binary operators between adjacent positions, specifically choosing either AND or OR for each gap.