I came across this post, which reports the following interview question:
Given two arrays of numbers, find if each of the two arrays have the same set of integers ? Suggest an algo which can run faster than NlogN without extra space?
The best that I can think of is the following:
(a) sort each array, and then (b) have two pointers moving along the two arrays and check if you find different values ... but step (a) has already NlogN complexity :(
(a) scan shortest array and put values into a map, and then (b) scan second array and check if you find a value that is not in the map ... here we have linear complexity, but we I use extra space
... so, I can't think of a solution for this question.
Ideas?
Thank you for all the answers. I feel many of them are right, but I decided to choose ruslik's one, because it gives an interesting option that I did not think about.