func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n, k;     cin >> n >> k;     deque<int> dq;     map<int, int> freq;     for (int i = 0; i < n; i++) {       int x;       cin >> x;       if (freq[x] == 0) {         if ((int)dq.size() < k)           dq.push_front(x);         else {           dq.push_front(x);           freq[dq.back()] = 0;           dq.pop_back();         }         freq[x] = 1;       }     }     cout << (int)dq.size() <<   n ;     for (auto i : dq) cout << i <<    ;     cout <<   n ;     return 0;   }   