88. Merge Sorted Array

https://leetcode.com/problems/merge-sorted-array/#/description

 

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.

 

 

Sol:

 

Rearrange m + n elements of nums1.

Suppose nums1 and nums2 are in ascending order. Check always put the larger element at index m+n-1 in nums1 until we run out of elements in nums1. If n is larger than m, it means there are n numbers in nums2 not copying to nums1 and then we copy them. 

 

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 > 0:
                nums1[:n] = nums2[:n]
                

 

 

This does not work when:

 

Input:[0] 0 [1] 1

Output:[0]

Expected:[1]