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() {
  int t;
  cin >> t;
  while (t--) {
    int n, index = -1, ans = INT_MIN;
    cin >> n;
    int arr[n];
    for (int i = 0; i < n; i++) cin >> arr[i];
    for (int i = 0; i < n; i++) {
      if (i == 0) {
        if (arr[i] > arr[i + 1]) {
          if (arr[i] > ans) {
            index = i;
            ans = arr[i];
          }
        }
      } else if (i == n - 1) {
        if (arr[i] > arr[i - 1]) {
          if (arr[i] > ans) {
            index = i;
            ans = arr[i];
          }
        }
      } else {
        if (arr[i] > arr[i - 1] || arr[i] > arr[i + 1]) {
          if (arr[i] > ans) {
            index = i;
            ans = arr[i];
          }
        }
      }
    }
    if (index != -1) index++;
    cout << index << "\n";
  }
  return 0;
}
