func_code_string: #include <bits/stdc++.h>   using namespace std;   bool used[100001];   int ans[100001], a[100001];   int main() {     int n;     cin >> n;     for (int i = 1; i <= n; i++) {       cin >> a[i];       if (a[i] <= n && !used[a[i]]) {         used[a[i]] = 1;         ans[i] = a[i];       }     }     int first = 1;     for (int i = 1; i <= n; i++) {       if (ans[i] == 0) {         while (used[first]) first++;         ans[i] = first;         first++;       }     }     for (int i = 1; i <= n; i++) {       cout << ans[i] <<    ;     }   }   