func_code_string: #include <bits/stdc++.h>   using namespace std;   mt19937 rnd(time(0));   const long long N = 3e5 + 7;   const long long MOD = 1e9 + 7;   long long pw(long long b, long long p) {     b %= MOD;     long long res = 1;     while (p > 0) {       if (p & 1) res = res * b % MOD;       b = b * b % MOD;       p >>= 1;     }     return res;   }   long long n, m, cur;   vector<vector<pair<long long, char>>> g(107);   bool vis[107][107][26], dp[107][107][26];   bool dfs(long long u, long long v, char ch) {     if (vis[u][v][ch -  a ]) return dp[u][v][ch -  a ];     for (auto i : g[u]) {       if (i.second >= ch && !dfs(v, i.first, i.second)) dp[u][v][ch -  a ] = 1;     }     vis[u][v][ch -  a ] = 1;     return dp[u][v][ch -  a ];   }   int32_t main() {     ios::sync_with_stdio(false);     cin.tie(0);     cin >> n >> m;     long long u, v;     char ch;     for (long long i = 1; i < m + 1; i++) {       cin >> u >> v >> ch;       g[u].emplace_back(v, ch);     }     for (long long i = 1; i < n + 1; i++) {       for (long long j = 1; j < n + 1; j++) {         if (dfs(i, j,  a ))           cout <<  A ;         else           cout <<  B ;       }       cout <<   n ;     }     return 0;   }   