Given two arrays nums1 and nums2, return a list [answer1,answer2] where answer1 contains all distinct integers in nums1 but not in nums2, and answer2 contains all distinct integers in nums2 but not in nums1.
For example, if nums1=[1,2,3] and nums2=[2,4,6], then answer1=[1,3] and answer2=[4,6].
This is the set difference operation applied twice. Try solving it before reading on.