Merge Sorted Array Python Solution with Tests

lcpy gen -n 88   # by problem number
lcpy gen -s merge_sorted_array   # by problem name

Input: nums1 = [1,2,3,0,0,0], m = 3, nums2 = [2,5,6], n = 3
Output: [1,2,2,3,5,6]

Input: nums1 = [1], m = 1, nums2 = [], n = 0
Output: [1]

Input: nums1 = [0], m = 0, nums2 = [1], n = 1
Output: [1]

class Solution:
    # Time: O(m + n)
    # Space: O(1)
    def merge(self, nums1: list[int], m: int, nums2: list[int], n: int) -> None:
        # Fill from the back to avoid overwriting nums1's real elements
        index = m + n - 1
        i = m - 1
        j = n - 1

        while i >= 0 and j >= 0:
            if nums1[i] > nums2[j]:
                nums1[index] = nums1[i]
                i -= 1
            else:
                nums1[index] = nums2[j]
                j -= 1
            index -= 1

        # Only nums2 leftovers can remain
        while j >= 0:
            nums1[index] = nums2[j]
            j -= 1
            index -= 1