https://leetcode-cn.com/problems/intersection-of-two-arrays/
class Solution:
def intersection(self, nums1: List[int], nums2: List[int]) -> List[int]:
res = []
s1 = set(nums1)
s2 = set(nums2)
for i in s1 & s2: #直接求交集
res.append(i)
return res