func_code_string: #include <bits/stdc++.h>   using namespace std;   string nums[1005];   string tostr(int a) {     ostringstream ss;     ss << a;     return ss.str();   }   deque<long long> deq;   vector<int> ans[200001];   vector<pair<int, int> > graph[200001];   int p[200001];   int cmax = 0;   void dfs(int v, int d) {     int c = 0;     for (int i = 0; i < graph[v].size(); i++) {       if (c == d) c++;       int k = graph[v][i].first;       if (k == p[v]) {         continue;       }       p[k] = v;       ans[c].push_back(graph[v][i].second);       dfs(k, c);       cmax = max(c, cmax);       c++;     }   }   set<int> is;   int main() {     int n, m;     cin >> n >> m;     int k;     for (int i = 0; i < n; i++) {       cin >> k;       is.insert(k);     }     vector<int> ans;     for (int kek = 1; kek <= 3000000; kek++) {       if (m >= kek && is.find(kek) == is.end()) {         ans.push_back(kek);         m -= kek;       }     }     cout << ans.size() <<   n ;     for (int i = 0; i < ans.size(); i++) {       cout << ans[i] <<    ;     }     return 0;   }   