414. Third Maximum Number

这一题很神奇，总觉得很简单， 但实际上在做的时候老出问题

class Solution(object):
    def thirdMax(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        v = [float("-inf"), float("-inf"), float("-inf")]
        for num in nums:
            if num not in v:
                if num > v[0]:
                    v = [num, v[0], v[1]]
                elif num > v[1]:
                    v = [v[0], num, v[1]]
                elif num > v[2]:
                    v = [v[0], v[1], num]
        if float("-inf") in v:
            return v[0]
        else:
            return v[2]
···