(Algorithm) Find if two unsorted arrays have any common elements in O(n) time without sorting?

Question

We have two unsorted arrays and each array has a length of n. These arrays contain random integers in the range of 0-n¹⁰⁰. How to find if these two arrays have any common elements in O(n)/linear time? Sorting is not allowed.

Answer 1

Hashtable will save you. Really, it's like a swiss knife for algorithms.
Just put in it all values from the first array and then check if any value from the second array is present.