leetode之Single Number II

这次的Single Number II是找粗来唯一一个出现次数不是3的数，有神器Counter在手，很简单的。代码如下：

class Solution(object):    def singleNumber(self, nums):        """        :type nums: List[int]        :rtype: int        """        from collections import Counter        a = Counter(nums)        for i in a.keys():            if a[i] != 3:                return i