Sort an Array in Wave Form

You are given an unsorted array ARR. Your task is to sort it so that it forms a wave-like array.

Input:

The first line contains an integer 'T', the number of test cases.
For each test case,
The first line contains a single integer 'N', the number of elements in the array.
The second line contains 'N' space-separated integers representing 'ARR'.

Output:

For each test case, output a single line with space-separated integers corresponding to the elements of a wave array.

Example:

If the given sequence ARR has N elements, it should follow the wave pattern:

ARR[0] >= ARR[1] and ARR[1] <= ARR[2]
ARR[2] >= ARR[3] and ARR[3] <= ARR[4]

For instance, ARR = { 4, 3, 5, 2, 3, 1, 2 } can be reorganized into a wave because:

4 > 3, 3 < 5
5 > 2, 2 < 3
3 > 1, 1 < 2

Constraints:

• 1 <= T <= 50
• 1 <= N <= 10^4
• -10^9 <= ARR[i] <= 10^9
• Time limit: 1 second

Note:

• The first element ARR[0] should be greater than or equal to ARR[1].
• There can be multiple valid wave arrays, return any one.
• Only implement the function, the output is automatically handled.