func_code_string: #include <bits/stdc++.h>   using namespace std;   map<int, int> mm;   map<int, int>::iterator it;   int x[100005];   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     int n;     cin >> n;     vector<int> v;     for (int i = 1; i <= n; i++) cin >> x[i];     for (int i = n; i >= 1; i--) {       if (mm[x[i]] == 0) {         mm[x[i]]++;         v.push_back(x[i]);       }     }     cout << endl;     cout << v.size() <<   n ;     for (int i = v.size() - 1; i >= 0; i--) {       cout << v[i] <<    ;     }   }   