func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 1001;   int n, a, b, u;   int sol[N][N];   void W() {     for (int i = 1; i <= n; i++) {       for (int j = 1; j <= n; j++) {         printf( %d , sol[i][j]);       }       printf(  n );     }   }   int main() {     cin >> n >> a >> b;     if (a != 1 && b != 1) {       cout <<  NO ;       return 0;     }     if (a == 1 && b == 1) {       if (n == 1) {         printf( YES n0 );         return 0;       }       if (n <= 3) {         cout <<  NO ;         return 0;       }       printf( YES n );       for (int i = 1; i < n; i++) {         sol[i][i + 1] = 1;         sol[i + 1][i] = 1;       }       W();       return 0;     }     printf( YES n );     if (a != 1)       u = a;     else       u = b;     for (int i = 1; i <= n - u; i++) {       sol[i][i + 1] = 1;       sol[i + 1][i] = 1;     }     if (a != 1) {       W();       return 0;     }     for (int i = 1; i <= n; i++) {       for (int j = 1; j <= n; j++) {         if (i != j) {           sol[i][j] ^= 1;         }       }     }     W();     return 0;   }   