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88. Merge Sorted Array

Let's have a look on the description of the problem:

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.

Merge nums1 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.

For this problem I was mainly thinking outside the box and came to a very elegant solution. Let’s have a deeper look into my solution:

  1. I created a new array where I merge the two arrays together and initialize it as empty for now.
  2. Now I shallow copy both of the arrays into my new one and use the python slicing mechanism starting from the first element until the element which is specified. After this I have all the elements which I want in my new array.
  3. Next I need to sort the array to have it in order, so I just the built-in python function sort().
  4. In the last step I shallow copy the initial array to the one I created and now the array has the correct reference.

The time and space complexity for this would be Big O(n).