what is cut off value in sorting algorithms?

Question

I was asked to do the quicksort, cut off with insertion sort. But I did not understand the meaning of cut off value. I need someone to elaborate this concept with real-world examples.

Answer 1

Some algorithms are asymptotically better than others. In your case, the asymptotic run time of Quicksort is O(N(logN)) while the asymptotic run time of insertion sort is O(N^2).

This means that for large values of N, Quicksort will run faster than insertion sort.

However, for small values of N, insertion sort may run faster. Hence, you can optimize the actual run-time of Quicksort by combining it with insertion sort for small array sizes.

Quicksort is a recursive algorithm, that breaks the original array into smaller arrays and runs recursively on each sub-array. Cut off with insertion sort means that once you reach array sizes smaller than some constant cut-off size, you sort these small arrays using insertion sort instead of continuing the recursion.