func_code_string: #include <bits/stdc++.h>   using namespace std;   vector<int> adj[100100], ans;   int arr[100100], cnt[100100];   bool visited[100100];   int n, m;   void dfs(int v) {     for (vector<int>::iterator it = adj[v].begin(); it != adj[v].end(); it++) {       cnt[*it]++;       if (cnt[*it] == arr[*it]) {         cnt[*it]++;         ans.push_back(*it);         dfs(*it);       }     }   }   int main() {     ios_base::sync_with_stdio(false);     cin.tie(nullptr);     cin >> n >> m;     int x, y;     for (int i = 1; i <= m; i++) {       cin >> x >> y;       adj[x].push_back(y);       adj[y].push_back(x);     }     for (int i = 1; i <= n; i++) cin >> arr[i];     for (int i = 1; i <= n; i++) {       if (cnt[i] == arr[i]) {         visited[i] = true;         cnt[i]++;         ans.push_back(i);         dfs(i);       }     }     cout << ans.size() <<   n ;     vector<int>::iterator it;     for (it = ans.begin(); it != ans.end(); it++) cout << *it <<    ;     return 0;   }   