func_code_string: #include <bits/stdc++.h>   using namespace std;   using namespace std;   const long long MOD = 1e9 + 7;   const int INF = 1e9;   int n, k, mn, mx, ans = INF;   int a[8] = {0, 1, 2, 3, 4, 5, 6, 7};   char s[8][10];   int main() {     ios::sync_with_stdio(0);     cin.tie(0);     cin >> n >> k;     for (int i = 0; i < n; i++) cin >> s[i];     int num;     do {       mn = 1e9;       mx = 0;       for (int i = 0; i < n; i++) {         num = 0;         for (int j = 0; j < k; j++) num = num * 10 + (s[i][a[j]] -  0 );         if (mn > num) mn = num;         if (mx < num) mx = num;       }       if (mx - mn < ans) ans = mx - mn;     } while (next_permutation(a, a + k));     cout << ans << endl;     return 0;   }   