LeetCode 88. Merge Sorted Array

Problem Statement

(Source) 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

,

Two Pointers

.

Solution

Use

Two Pointers

to

greedily

choose the larger one from end s of the two array, and update the next insertion position by one cell.

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.
        """
        pos = m + n - 
        i, j = m - , n - 
        while j >= :
            if i >=  and nums1[i] > nums2[j]:
                nums1[pos] = nums1[i]
                i -= 
            else:
                nums1[pos] = nums2[j]
                j -= 
            pos -= 
           

Complexity Analysis:

• Time Complexity: O(m+n) .
• Space Complexity: O(1) .