Untitled

#include <bits/stdc++.h>
    
using namespace std;
 
int max_el(vector<int> a) {
    int res = -1e9;
    for (int i = 0; i < a.size(); ++i)
        if (a[i] > res)
            res = a[i];
    return res;
}
 
int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
 
    int n;
    cin >> n;
    vector<int> permutation(n);
    for (int& elem : permutation)
        cin >> elem;
    for (int i = 0; i < n; ++i)
        if (permutation[i] > n) {
            cout << "-1\n";
            return 0;
        }
    int max_elem = max_el(permutation);
    vector<int> a(max_elem, 0);
    for (int i = 0; i < n; ++i) {
        if (permutation[i] != 0) {
            if (a[permutation[i] - 1] == 0)
                a[permutation[i] - 1] = 1;
            else if (a[permutation[i] - 1] == 1) {
                cout << "-1\n";
                return 0;
            }
        }
    }
    vector<int> b;
    for (int i = 0; i < a.size(); ++i) 
        if (a[i] == 0)
            b.push_back(i + 1);
    for (int i = 0, j = 0; i < permutation.size(); ++i)
        if (permutation[i] == 0) {
            if (b.size() != 0) {
                permutation[i] = b.back();
                b.pop_back();
            } else 
                permutation[i] = max_elem + (++j);
        }
    for (int elem : permutation)
        cout << elem << ' ';
}