Merge Sorted Array

Question

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

Note: You may assume that nums1 has enough space (size that is greater or equal to m + n) to hold additional elements from nums2. The number of elements initialized in nums1 and nums2 are m and n respectively.

Tags

• Array

Thought

Since the extra space is at the end of the array nums1, we start to merge two arrays from the end of two arrays.

Code

class Solution(object):
    def merge(self, nums1, m, nums2, n):
        """
        :type nums1: List[int]
        :type m: int
        :type nums2: List[int]
        :type n: int
        :rtype: void Do not return anything, modify nums1 in-place instead.
        """
        while m > 0 and n > 0:
            if nums1[m - 1] > nums2[n - 1]:
                nums1[m + n - 1] = nums1[m - 1]
                m -= 1
            else:
                nums1[m + n - 1] = nums2[n - 1]
                n -= 1
        if n > m:
            nums1[:n] = nums2[:n]