codeforces-1023 C Bracket Subsequence

 1 #include <iostream>
 2 #include <unordered_map>
 3 #include <algorithm>
 4 #include <vector>
 5 #include <queue>
 6 
 7 using namespace std;
 8 
 9 int main()
10 {
11     int n,k;
12     while(cin >> n >> k)
13     {
14         string input;
15         cin >> input;
16         string result;
17         int right_existed = 0;
18         int left = 0;
19         int right = 0;
20         for(int i = 0; i < n; i ++)
21         {
22             if(right_existed!=k/2)
23             {
24                 result += input[i];
25                 if(input[i]=='(')
26                 {
27                     right_existed ++;
28                     left ++;
29                 }
30                 else
31                     right ++;
32             }
33         }
34         int tmp = left - right;
35         while(tmp--)
36             result += ')';
37         cout << result << endl;
38     }
39     return 0;
40 }