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;
    cin >> n;
    int a[n + 9];
    int m = 0;
    for (int i = 1; i <= n; i++) {
      cin >> a[i];
      m = max(m, a[i]);
    }
    int index = -1;
    for (int i = 1; i <= n; i++) {
      if (a[i] == m && ((a[i] > a[i + 1]) || (a[i] > a[i - 1]))) {
        index = i;
      }
    }
    cout << index << endl;
  }
}
