#include <iostream>

using namespace std;

int
main ()
{
  int t;
  int size;
  bool same = false;
  cin >> t;
  int a[t];
  for (int i = 0; i < t; i++)
    {
      same = false;
      cin >> size;
      for (int j = 0; j < size; j++)
        {
          cin >> a[j];
        }
      for (int j = 0; j < size; j++)
        {
          for (int k = j + 1; k < size; k++)
            {
              if (a[j] == a[k])
                {
                  same = true;
                }
             }
        }
      if (same == false)
        {
          cout << "YES" << endl;
        }
      else if (same == true)
        {
          cout << "NO" << endl;
        }
    }

  return 0;
}