leetcode

Intersection of Two Arrays II

Intersection of Two Arrays II

dict version

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class Solution(object):
    def intersect(self, nums1, nums2):
        """
        :type nums1: List[int]
        :type nums2: List[int]
        :rtype: List[int]
        """
        cnt = {}
        res = []
        for x in nums1:
            cnt[x] = cnt.get(x, 0) + 1
        for x in nums2:
            if x in cnt and cnt[x] > 0:
                res.append(x)
                cnt[x] -= 1
        return res

Counter version

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import collections
class Solution(object):
    def intersect(self, nums1, nums2):
        """
        :type nums1: List[int]
        :type nums2: List[int]
        :rtype: List[int]
        """
        a, b = map(collections.Counter, (nums1, nums2))
        return list((a & b).elements())

output

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In [270]: s = Solution(); t = s.intersect([4,9,5,4], [9,4,9,8,4])
In [271]: t
Out[271]: [9, 4, 4]

leet code