Merge Sorted Array
Created: October 8, 2018 by [lek-tin]
Last updated: October 8, 2018
Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array.
Note
The number of elements initialized in nums1 and nums2 are m and n respectively. You may assume that nums1 has enough space (size that is greater or equal to m + n) to hold additional elements from nums2.
Example
Input:
nums1 = [1,2,3,0,0,0], m = 3 nums2 = [2,5,6], n = 3
Output: `[1,2,2,3,5,6]`
Solution
# Time: o(m+n)
# Space: o(1)
class Solution:
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.
"""
i, j, k = m-1, n-1, m+n-1
while i >= 0 and j >= 0:
if nums1[i] >= nums2[j]:
nums1[k] = nums1[i]
i -= 1
else:
nums1[k] = nums2[j]
j -= 1
k -= 1
# nums1 holds the result
# For example, if nums1 = [7, 8, 9], nums2=[1, 2], when nums1 has been iterated completely(i<0), j needs to keep iterating till it reaches 0 index.
while j >= 0:
nums1[k] = nums2[j]
k -= 1
j -= 1