rYnd1K - Online C++ Compiler & Debugging Tool

#include <bits/stdc++.h>
using namespace std;

const int N = 1e5 + 5;
int a[N];
signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL), cout.tie(NULL);
    int n;
    cin >> n;
    vector<int> v;
    for(int i = 1; i <= n; ++i)
        cin >> a[i], v.push_back(a[i]);
    sort(v.begin(), v.end());
    v.erase(unique(v.begin(), v.end()), v.end());
    for(int i = 1; i <= n; ++i)
        a[i] = lower_bound(v.begin(), v.end(), a[i]) - v.begin() + 1;
    return 0;
}