CF1821E.Rearrange Brackets

普及/提高-

通过率:0%

AC君温馨提醒

该题目为【codeforces】题库的题目,您提交的代码将被提交至codeforces进行远程评测,并由ACGO抓取测评结果后进行展示。由于远程测评的测评机由其他平台提供,我们无法保证该服务的稳定性,若提交后无反应,请等待一段时间后再进行重试。

题目描述

A regular bracket sequence is a bracket sequence that can be transformed into a correct arithmetic expression by inserting characters "1" and "+" between the original characters of the sequence. For example:

  • bracket sequences "()()" and "(())" are regular (the resulting expressions are: "(1)+(1)" and "((1+1)+1)");
  • bracket sequences ")(", "(" and ")" are not.

You are given a regular bracket sequence. In one move, you can remove a pair of adjacent brackets such that the left one is an opening bracket and the right one is a closing bracket. Then concatenate the resulting parts without changing the order. The cost of this move is the number of brackets to the right of the right bracket of this pair.

The cost of the regular bracket sequence is the smallest total cost of the moves required to make the sequence empty.

Actually, you are not removing any brackets. Instead, you are given a regular bracket sequence and an integer kk . You can perform the following operation at most kk times:

  • extract some bracket from the sequence and insert it back at any position (between any two brackets, at the start or at the end; possibly, at the same place it was before).

After all operations are performed, the bracket sequence has to be regular. What is the smallest possible cost of the resulting regular bracket sequence?

输入格式

The first line contains a single integer tt ( 1t1041 \le t \le 10^4 ) — the number of testcases.

The first line of each testcase contains a single integer kk ( 0k50 \le k \le 5 ) — the maximum number of operations you can perform.

The second line contains a non-empty regular bracket sequence, it consists only of characters '(' and ')'.

The total length of the regular bracket sequences over all testcases doesn't exceed 21052 \cdot 10^5 .

输出格式

For each testcase, print a single integer — the smallest possible cost of the regular bracket sequence after you perform at most kk operations on it.

输入输出样例

  • 输入#1

    7
    0
    ()
    0
    (())
    1
    (())
    5
    ()
    1
    (()()(()))
    2
    ((())()(()())((())))
    3
    ((())()(()())((())))

    输出#1

    0
    1
    0
    0
    1
    4
    2
首页