【Leetcode】349. Intersection of Two Arrays

class Solution1(object):
    def intersection(self, nums1, nums2):
        """
        use set intersection
        """
        return list(set(nums1).intersection(set(nums2)))

class Solution2(object):
    def intersection(self, nums1, nums2):
        """
        use dictionary, dictionary used to store num already appear to avoid redundancy
        """
        dict1, dict2 = {}, {}
        result = []
        for num in nums1:
            dict1[num] =1
        for num in nums2:
            if num in dict1 and num not in dict2:
                result.append(num)
            dict2[num] =1
        return result