func_code_string: #include <bits/stdc++.h>   const double eps = 1e-9;   const int MOD = int(1e9) + 7;   const int MaxN = int(2e5) + 256;   using namespace std;   int n, a, b;   int main() {     cin >> n >> a >> b;     if (n > a * b) {       cout << -1;       return 0;     }     int cnt = 1;     bool ok = true, r = true;     for (int i = 1; i <= a; i++) {       if (r) {         for (int j = 1; j <= b; j++) {           if (cnt <= n)             cout << cnt++ <<    ;           else             cout << 0 <<    ;         }         r = false;       } else {         cnt += b - 1;         for (int j = 1; j <= b; j++) {           if (cnt <= n)             cout << cnt <<    ;           else             cout << 0 <<    ;           cnt--;         }         cnt += b + 1;         r = true;       }       cout << endl;     }   }   