Codeforces Round 204 (Div. 1)

5 problems from Codeforces Round 204 (Div. 1) (contest 351), difficulty 1800-2700. 5/5 solutions verified against sample I/O.

5 items

Codeforces Round 204 (Div. 1)

Div. 1 | 5 problems | 5/5 verified | Difficulty 1800-2700 | 9m 11s

#	Problem	Rating	Tags	Accepted	Time	✓
A	Jeff and Rounding	1800	dp, greedy, implementation	3,096	1m 31s	✓
B	Jeff and Furik	1900	combinatorics, dp, probabilities	2,724	1m 56s	✓
C	Jeff and Brackets	2500	dp, matrices	630	1m 29s	✓
D	Jeff and Removing Periods	2700	data-structures	1,345	2m 39s	✓
E	Jeff and Permutation	2200	greedy	1,792	1m 36s	✓

Practice › Codeforces Solutions › Codeforces Round 204 (Div. 1) ›

CF 351C - Jeff and Brackets

We are asked to construct a bracket sequence of length n·m, where n is a small number up to 20 and m is much larger, up to 10^7, and is even. Each position in the sequence can be either an opening bracket ( or a closing bracket ).

Practice › Codeforces Solutions › Codeforces Round 204 (Div. 1) ›

CF 351A - Jeff and Rounding

Jeff has a list of 2n real numbers and he wants to round them in pairs so that the total sum changes as little as possible. Each operation consists of taking two unused numbers: one is rounded down (floor) and the other rounded up (ceiling).

Practice › Codeforces Solutions › Codeforces Round 204 (Div. 1) ›

CF 351E - Jeff and Permutation

We are given a sequence of integers, and we are allowed to flip the sign of any element. The goal is to minimize the number of inversions in the sequence. An inversion occurs whenever a larger number appears before a smaller number in the sequence.

Practice › Codeforces Solutions › Codeforces Round 204 (Div. 1) ›

CF 351D - Jeff and Removing Periods

For each query we look at a subarray of the given array and ask for its beauty. A single operation chooses several equal values whose positions form an arithmetic progression, removes them, and then allows us to reorder everything that remains. That last sentence is the key.

Practice › Codeforces Solutions › Codeforces Round 204 (Div. 1) ›

CF 351B - Jeff and Furik

We are asked to model a two-player game played on a permutation of integers from 1 to n. Jeff moves first and can swap any adjacent elements.