Find the Second Largest Element

Given an array or list of integers 'ARR', identify the second largest element in 'ARR'.

If a second largest element does not exist, return -1.

Example:

Input:

ARR = [2, 4, 5, 6, 8]

Output:

6

Explanation:

In the sequence, 8 is the largest and 6 is the second largest.

Input:

ARR = [5, 5, 5, 5, 5]

Output:

-1

Explanation:

There is no second largest element as all elements are identical.

Constraints:

• 1 ≤ T ≤ 100 where 'T' is the number of test cases.
• 1 ≤ N ≤ 5000 where 'N' is the number of elements in 'ARR'.
• -10^9 ≤ ARR[i] ≤ 10^9 for each element in 'ARR'.

Note:

You do not need to print any output. Implement the function to return the desired results.