merge_sorted_array.py

from typing import List


class Solution:
    def merge(self, nums1: List[int], m: int, nums2: List[int], n: int) -> None:
        """
        Do not return anything, modify nums1 in-place instead.
        """
        k = m+n-1
        m = m-1
        n = n-1
        while m>=0 and n>=0:
            if nums1[m] > nums2[n]:
                nums1[k] = nums1[m]
                m -= 1
            else:
                nums1[k] = nums2[n]
                n -= 1
            k -= 1
        while n >= 0:
            nums1[k] = nums2[n]
            k -= 1
            n -= 1
        return nums1
    #space: O(1), time: O(m+n)

print(Solution().merge([4,5,6,0,0,0],3,[1,2,3],3))