func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n, k, a;     cin >> n >> k;     list<int> lst;     map<int, bool> vis;     for (int i = 0; i < n; i++) {       cin >> a;       if (lst.size() < k) {         if (vis.find(a) == vis.end()) {           lst.push_front(a);           vis[a] = true;         }         continue;       }       if (vis.find(a) == vis.end() || vis[a] == false) {         vis[a] = true;         vis[lst.back()] = false;         lst.pop_back();         lst.push_front(a);       }     }     cout << lst.size() << endl;     for (auto it = lst.begin(); it != lst.end(); it++) cout << (*it) <<    ;     cout << endl;     return 0;   }   