func_code_string: #include <bits/stdc++.h>   using namespace std;   const int MAXN = 100100;   int N, M;   int app[MAXN];   char type[MAXN];   int P[MAXN];   bool check(int leader) {     set<int> users;     users.insert(leader);     for (int i = 0; i < M; i++) {       if (type[i] ==  + )         users.insert(P[i]);       else         users.erase(P[i]);       if (!users.empty() && users.find(leader) == users.end()) return false;     }     return true;   }   int main() {     cin >> N >> M;     for (int i = 0; i < M; i++) cin >> type[i] >> P[i];     int offp = 0;     for (int i = 0; i < M; i++) {       if (type[i] ==  -  && !app[P[i]]) offp = P[i];       app[P[i]] = true;     }     if (offp != 0) {       if (check(offp)) app[offp] = false;     } else {       if (check(P[0])) app[P[0]] = false;     }     int total = 0;     for (int i = 1; i <= N; i++) total += !app[i];     cout << total <<   n ;     for (int i = 1; i <= N; i++)       if (!app[i]) cout << i <<    ;     return 0;   }   