**Solution**

**Intersection of Two Arrays** https://leetcode.com/problems/intersection-of-two-arrays/?tab=Description

**Algorithm**

- Use a set to store all numbers from nu1.
- Then test membership of num2 in this set. Keep results in another set so that they are automatically deduped.

```
class Solution(object):
def intersection(self, nums1, nums2):
"""
:type nums1: List[int]
:type nums2: List[int]
:rtype: List[int]
"""
nums1_set = set(nums1)
result_set = set([])
for x in nums2:
if x in nums1_set and x not in result_set:
result_set.add(x)
return [x for x in result_set]
```