func_code_string: #include <bits/stdc++.h>   using namespace std;   vector<pair<int, int> > g[110];   char s[2];   int n, m, x, y, f[110][110][27];   int dp(int x, int y, int k) {     if (f[x][y][k] != 0) return f[x][y][k];     int ret = 1;     for (auto e : g[x])       if (e.second >= k) ret = min(ret, dp(y, e.first, e.second));     f[x][y][k] = -ret;     return f[x][y][k];   }   int main() {     scanf( %d%d , &n, &m);     for (int i = 1; i <= m; i++) {       scanf( %d%d%s , &x, &y, s);       g[x].push_back(pair<int, int>(y, s[0] -  a ));     }     for (int i = 1; i <= n; i++) {       for (int j = 1; j <= n; j++) {         for (int k = 0; k < 26; k++) f[i][j][k] = dp(i, j, k);         if (f[i][j][0] > 0)           cout <<  A ;         else           cout <<  B ;       }       cout << endl;     }     return 0;   }   