Question

I’ve been trying to figure this out for a while and I just cant get it. Any help would be great. I’m programming in C++.

Find a run time of O(n^3 log n) using two looping structures.

Answer 1

Assuming that this is a homework, here is a hint: you need to put an O(N*LogN) operation inside your two nested loops such that the operation does not need a loop.

For example, you can start with an array of N items, do nested loops on i and j that reverse array elements between i and j, and then sort the resulting array. Reversing is O(N), sorting is O(N*LogN), so sorting dominates; two outer loops provide the remaining O(N^2). Both sorting and reversing can be done using standard library functions, without additional loops.