Merge 2 sorted arrays with constant space.

main.py

'''
Simplest Approach( O(1) extra space without using Insertion Sort)

Time Complexity: O(nlogn) => As we sort both the arrays at the end.
Space Complexity: O(1) => apart from I/O

Procedure/Algo
1.
Take two pointers , lets call them ptr1 and ptr2.
ptr1 runs from end of array1 till the first element. ( endIndex -> 0 )
ptr2 runs from first element of array2 till the last element. (0 -> endIndex )

2.
Use a while loop which runs till ptr1 >=0 && ptr2< array2.length
2.1
Now swap the elements of array1 and array2 IF (array1 [ptr1] > array2[ptr2] )
(The reason we swap is because all the smaller elements should be in array1 and the larger elements should be in
array2.In other words, the largest element of array1 should be lesser than the smallest element of array2)

3.
Finally sort both array1 and array2
'''
for _ in range(int(input())):
	n, m = map(int,input().split())
	arr = input().split()
	for i in range(n):
		arr[i] = int(arr[i])
	brr = input().split()
	for i in range(m):
		brr[i] = int(brr[i])
	
	i, j = n - 1, 0
	while i >= 0 and j < m:
		if arr[i] > brr[j]:
			arr[i], brr[j] = brr[j], arr[i]
			j += 1
		else:
			i -= 1

	arr.sort()
	brr.sort()

	print(*arr, end=" ")
	print(*brr)