1
3
5 3 4
 6
5
5 3 4 4 5
3
1 1 1
5
4 4 3 4 4
5
5 5 4 3 2
3
1 1 2
5
5 4 3 5 5
 1
3
10 1 5

1
 1
-1
2
2
3
1
 1

#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int t;
  cin >> t;
  while (t--) {
    int num;
    cin >> num;
    int arr[num], i, as = -1, mx = 0;
    for (i = 0; i < num; i++) {
      cin >> arr[i];
      mx = max(mx, arr[i]);
    }
    for (i = 0; i < num; i++) {
      if (arr[i] == mx) {
        if (i - 1 >= 0 && arr[i - 1] != mx) {
          as = i + 1;
          break;
        }
        if (i + 1 < num && arr[i + 1] != mx) {
          as = i + 1;
          break;
        }
      }
    }
    cout << as << "\n";
  }
}
