func_code_string: #include <bits/stdc++.h>   using namespace std;   const int inf = 1e9 + 7;   const int maxn = 21;   char s[maxn][maxn];   int dp[1 << maxn], a[maxn][maxn], cost[maxn][maxn], same[maxn][maxn];   int main() {     int n, m;     ios::sync_with_stdio(false);     cin >> n >> m;     for (int i = 0; i < n; i++)       for (int j = 0; j < m; j++) cin >> s[i][j];     for (int i = 0; i < n; i++)       for (int j = 0; j < m; j++) cin >> a[i][j];     for (int i = 0; i < n; i++) {       for (int j = 0; j < m; j++) {         int sum = 0, ma = 0;         for (int k = 0; k < n; k++) {           if (s[i][j] == s[k][j]) {             sum += a[k][j];             ma = max(ma, a[k][j]);             same[i][j] |= (1 << k);           }         }         cost[i][j] = sum - ma;       }     }     for (int i = 1; i < (1 << n); i++) dp[i] = inf;     for (int i = 0; i < (1 << n); i++) {       for (int j = 0; j < n; j++) {         for (int k = 0; k < m; k++) {           dp[i | (1 << j)] = min(dp[i | (1 << j)], dp[i] + a[j][k]);           dp[i | same[j][k]] = min(dp[i | same[j][k]], dp[i] + cost[j][k]);         }       }     }     cout << dp[(1 << n) - 1] << endl;     return 0;   }   