You are given two integer arrays nums1 and nums2, sorted in non-decreasing order, and two integers m and n, representing the number of elements in nums1 and nums2 respectively.
Mergenums1 and nums2 into a single array sorted in non-decreasing order.
The final sorted array should not be returned by the function, but instead be stored inside the array nums1. To accommodate this, nums1 has a length of m + n, where the first m elements denote the elements that should be merged, and the last n elements are set to 0 and should be ignored. nums2 has a length of n.
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] Explanation: The arrays we are merging are [1,2,3] and [2,5,6]. The result of the merge is [1,2,2,3,5,6] with the underlined elements coming from nums1.
Example 2:
Input: nums1 = [1], m = 1, nums2 = [], n = 0 Output: [1] Explanation: The arrays we are merging are [1] and []. The result of the merge is [1].
Example 3:
Input: nums1 = [0], m = 0, nums2 = [1], n = 1 Output: [1] Explanation: The arrays we are merging are [] and [1]. The result of the merge is [1]. Note that because m = 0, there are no elements in nums1. The 0 is only there to ensure the merge result can fit in nums1.
Constraints:
nums1.length == m + nnums2.length == n0 <= m, n <= 2001 <= m + n <= 200-109 <= nums1[i], nums2[j] <= 109
Follow up: Can you come up with an algorithm that runs in O(m + n) time?
1class Solution:
2 def merge(self, nums1: List[int], m: int, nums2: List[int], n: int) -> None:
3 """
4 Do not return anything, modify nums1 in-place instead.
5 """
6 # Start from the end of nums1 and nums2
7 p1, p2, p = m - 1, n - 1, m + n - 1
8
9 # Merge in reverse order
10 while p1 >= 0 and p2 >= 0:
11 if nums1[p1] > nums2[p2]:
12 nums1[p] = nums1[p1]
13 p1 -= 1
14 else:
15 nums1[p] = nums2[p2]
16 p2 -= 1
17 p -= 1
18
19 # If there are remaining elements in nums2, add them
20 while p2 >= 0:
21 nums1[p] = nums2[p2]
22 p2 -= 1
23 p -= 1
24