138. Intersection of two sorted arrays

Given 2 sorted array of integers, find the elements that exist in both arrays.

intersect(  [1,2,2,3,4,4],  [2,2,4,5,5,6,2000])

1. The arrays might have duplicate numbers.
2. The order of returning result doesn't matter.
3. What is the time & space cost of your approach? Could you improve it?