func_code_string: #include <bits/stdc++.h>   using namespace std;   const int inf = 0x3f3f3f3f, N = 10;   int ans = inf, n, k, idx[N];   char arr[N][N];   int convert(int num) {     int ret = 0;     for (int i = 0; i < k; ++i) {       ret = (ret * 10) + (arr[num][idx[i]] -  0 );     }     return ret;   }   int main() {     cin >> n >> k;     for (int i = 0; i < k; ++i) idx[i] = i;     for (int i = 0; i < n; ++i) scanf( %s , arr[i]);     do {       int mn = inf, mx = 0;       for (int i = 0; i < n; ++i) {         mn = min(mn, convert(i));         mx = max(mx, convert(i));       }       ans = min(ans, mx - mn);     } while (next_permutation(idx, idx + k));     cout << ans;     return 0;   }   