func_code_string: #include <bits/stdc++.h>   using namespace std;   int const MAX = 2005;   int mp[MAX][MAX];   int main() {     int n;     bool flag = true;     scanf( %d , &n);     for (int i = 1; i <= n; i++)       for (int j = 1; j <= n; j++) scanf( %d , &mp[i][j]);     for (int i = 1; i <= n; i++) {       for (int j = 1; j <= n; j++) {         if (mp[i][i] || mp[i][j] != mp[j][i] || (i != j && !mp[i][j])) {           printf( NO n );           return 0;         }       }     }     for (int i = 1; i <= n; i++) {       int u = 1;       for (int j = 1; j <= n; j++) {         if (i == j) continue;         if (mp[i][j] < mp[i][u]) u = j;       }       for (int j = 1; j <= n; j++) {         if (i == j) continue;         if (abs(mp[i][j] - mp[j][u]) != mp[i][u]) {           printf( NO n );           return 0;         }       }     }     printf( YES n );   }   