func_code_string: #include <bits/stdc++.h>   using namespace std;   const int maxn = 1e5 + 10;   int b[maxn];   char a[maxn];   int num[2 * maxn];   int main() {     int n;     scanf( %d , &n);     int count0 = 0, count1 = 0;     memset(num, -1, sizeof(num));     int len = 0, maxlen = 0;     scanf( %s , a + 1);     for (int i = 1; i <= n; i++) {       if (a[i] ==  0 )         count0++;       else         count1++;       b[i] = count1 - count0;       if (b[i] == 0) {         if (maxlen < i) maxlen = i;         continue;       }       if (num[b[i] + maxn] == -1)         num[b[i] + maxn] = i;       else {         len = i - num[b[i] + maxn];         if (maxlen < len) maxlen = len;       }     }     printf( %d n , maxlen);     return 0;   }   