func_code_string: #include <bits/stdc++.h>   using namespace std;   const int MAXN = 1e5 + 5;   const int INF = 1e9 + 7;   vector<int> adjList[MAXN];   vector<int> vec;   bool visited[MAXN];   void dfs(int start) {     visited[start] = true;     for (auto u : adjList[start]) {       if (!visited[u]) {         dfs(u);       }     }     vec.push_back(start);   }   int main() {     int n, m;     cin >> n >> m;     for (int i = 0; i < m; ++i) {       int c, d;       cin >> c >> d;       adjList[c].push_back(d);     }     for (int i = 1; i <= n; ++i) {       if (!visited[i]) {         vec.clear();         dfs(i);         for (auto u : vec) {           cout << u <<    ;         }       }     }   }   