mergeSortedArray.py

"""
Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array.

The number of elements initialized in nums1 and nums2 are m and n respectively.
You may assume that nums1 has a size equal to m + n such that it has enough space to hold additional elements from nums2

Example 1:

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

"""


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.
        """
        # Since we will be using num1 as the array to append num2 values. Have slots to accommodate this
        # Hence the k pointer which is (m + n) - 1
        i = m - 1
        j = n - 1
        k = (m + n) - 1

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

        while j >= 0:
            nums1[k] = nums2[j]
            k -= 1
            j -= 1