一道小题

#include <iostream>
#include <algorithm>
using namespace std;
int main() {
    int T;
    cin >> T;
    while (T--) {
        int n;
        cin >> n;
        int a[n];
        for (int i = 0; i < n; i++) cin >> a[i];
        sort(a, a + n);
        bool flag = true;
        for (int i = 1; i < n; i++) {
            if (a[i] == a[i - 1]) {
                flag = false;
                break;
            }
        }
        if (flag) cout << "YES" << endl;
        else cout << "NO" << endl;
    }
    return 0;
}