func_code_string: #include <bits/stdc++.h>   using namespace std;   string s[11];   int a[11];   int n, k;   int ans = 0x7fffffff;   string t[11];   int num[11];   int main() {     cin >> n >> k;     for (int i = 0; i < n; i++) {       cin >> s[i];     }     for (int i = 0; i < k; i++) {       a[i] = i;     }     do {       for (int i = 0; i < n; i++) {         for (int j = 0; j < k; j++) {           t[i][j] = s[i][a[j]];         }       }       for (int i = 0; i < n; i++) {         int tt = 0;         for (int j = 0; j < k; j++) {           tt = tt * 10 + t[i][j] -  0 ;         }         num[i] = tt;       }       sort(num, num + n);       ans = min(ans, num[n - 1] - num[0]);     } while (next_permutation(a, a + k));     cout << ans << endl;     return 0;   }   