Finding common elements in two arrays of different size

Question

I have a problem to find common elements in two arrays and that\'s of different size.

Take , Array A1 of size n and Array A2 o

Answer 1

In Python, you would write set(A1).intersection(A2). This is the optimal O(n + m).

There's ambiguity in your question though. What's the result of A1=[0, 0], A2=[0, 0, 0]? There's reasonable interpretations of your question that give 1, 2, 3, or 6 results in the final array - which does your situation require?