Codeforces Round 243 (Div. 1)

5 problems from Codeforces Round 243 (Div. 1) (contest 425), difficulty 1500-2500. 3/5 solutions verified against sample I/O.

5 items

Codeforces Round 243 (Div. 1)

Div. 1 | 5 problems | 3/5 verified | Difficulty 1500-2500 | 10m 7s

#	Problem	Rating	Tags	Accepted	Time	✓
A	Sereja and Swaps	1500	brute-force, sortings	4,164	4m 46s
B	Sereja and Table	2200	bitmasks, greedy	1,412	1m 20s	✓
C	Sereja and Two Sequences	2300	data-structures, dp	983	1m 37s	✓
D	Sereja and Squares	2300	binary-search, data-structures, hashing	1,630	35s	✓
E	Sereja and Sets	2500	dp	803	1m 49s

Practice › Codeforces Solutions › Codeforces Round 243 (Div. 1) ›

CF 425C - Sereja and Two Sequences

We have two sequences. A profitable move chooses a non-empty prefix from each sequence, with the requirement that the last element of the chosen prefix in the first sequence is equal to the last element of the chosen prefix in the second sequence.

Practice › Codeforces Solutions › Codeforces Round 243 (Div. 1) ›

CF 425A - Sereja and Swaps

We are given an array of integers and a limited budget of swap operations. Each swap allows exchanging any two positions in the array, and we can perform at most k such swaps.

Practice › Codeforces Solutions › Codeforces Round 243 (Div. 1) ›

CF 425E - Sereja and Sets

We are asked to count sets of intervals within the integer range from 1 to n, such that the largest collection of non-overlapping intervals in the set has exactly size k.

Practice › Codeforces Solutions › Codeforces Round 243 (Div. 1) ›

CF 425B - Sereja and Table

We are given a table of size n × m, where each cell contains either a zero or a one. Sereja wants to modify at most k cells so that the table satisfies a very specific property: each connected group of identical numbers must form a perfect rectangle aligned with the table’s…

Practice › Codeforces Solutions › Codeforces Round 243 (Div. 1) ›

CF 425D - Sereja and Squares

We are given a set of $n$ points on a 2D plane, each with integer coordinates, and all points are distinct. The task is to count how many axis-aligned squares exist whose four corners are all points from this set.