Merge Sort Task

Given a sequence of numbers, denoted as ARR, your task is to return a sorted sequence of ARR in non-descending order using the Merge Sort algorithm.

Example:

Explanation:

The Merge Sort algorithm is based on Divide and Conquer. It splits the input array into two parts, continuing until each part has a size of '1'. It then merges the sorted arrays to return one fully sorted array.

The above illustration shows how merge sort works.

Input:

The first line of input contains an integer T denoting the number of test cases.
The next 2*T lines represent the T test cases.
The first line of each test case contains an integer N which denotes the size of ARR.
The second line of each test case contains N space-separated elements of ARR.

Output:

For each test case, output the numbers in non-descending order.

Constraints:

• 1 ≤ T ≤ 50
• 1 ≤ N ≤ 10^4
• -10^9 ≤ arr[i] ≤ 10^9
• Time Limit: 1 sec

Note:

It is compulsory to use the 'Merge Sort' algorithm.
You are not required to print the expected output; it has already been taken care of. Just implement the function.