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(0);
  cin.tie(0);
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    int arr[n];
    int biggest = INT_MIN;
    bool dominantexiist = false;
    for (int i = 0; i < n; i++) {
      cin >> arr[i];
      biggest = max(biggest, arr[i]);
    }
    int ans;
    for (int i = 0; i < n; i++) {
      if (biggest = arr[i]) {
        if (arr[i + 1] < n && arr[i] > arr[i + 1]) {
          ans = i;
          dominantexiist = true;
          break;
        }
        if (arr[i - 1] >= 0 && arr[i] > arr[i - 1]) {
          ans = i;
          dominantexiist = true;
          break;
        }
      }
    }
    if (dominantexiist)
      cout << ans + 1 << "\n";
    else
      cout << "-1"
           << "\n";
  }
  return 0;
}
