func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 400005;   char a[N];   int n, k, delta, top, st[N];   bool vis[N];   int main() {     scanf( %d%d , &n, &k), scanf( %s , a + 1);     delta = (n - k) / 2, top = 0;     for (int i = 1; i <= n; ++i) {       if (a[i] ==  ( )         st[++top] = i;       else {         if (delta) {           --delta, vis[i] = 1;           vis[st[top]] = 1;         }         --top;       }     }     for (int i = 1; i <= n; ++i)       if (!vis[i]) printf( %c , a[i]);     puts(  );     return 0;   }   