Question

if I have an array with cells 0-N that sorted, and cells N+1 until M+N, not sorted.
what will be the best time complexity to sort the array?

thanks!

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Edit:

thanks !! If I want to do that in-place, it will change the complexity?

Answer 1

First, sort just the M unsorted elements. This takes time O(M log M) using a comparison-based sort (like quicksort, merge sort, or heap sort).

Then merge the two sorted segments (of lengths N and M) together. This takes time O(M + N).

So the best time complexity, using a comparison-based sorted, is O(M + N + M log M).