Odd Occurrence Element Problem Statement

Given an array of integers where each element appears an even number of times except for one element which appears an odd number of times, find the element that appears an odd number of times.

Input:

Number of test cases: T
For each test case, you will receive:
- An integer N, the size of the array.
- An array of N space-separated integers.

Output:

For each test case, return the integer that appears an odd number of times.

Example:

Input:

5 5
5 6 4 6

Output:

4

Constraints:

• 1 ≤ T ≤ 100
• 1 ≤ N ≤ 10000
• 1 ≤ ARR[i] ≤ 10^8
• ARR contains integers that repeat an even number of times except one integer.

Note:

The function itself does not handle printing. Simply implement the logic and return the value.