python leetcode 日记 --Contains Duplicate --217

题目

Given an array of integers, find if the array contains any duplicates. Your function should return true if any value appears at least twice in the array, and it should return false if every element is distinct.

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输入输出如下：

        """
        :type nums: List[int]
        :rtype: bool
        """

浏览题目，如果遍历每一个元素，不可避免的复杂度将达到o（n²）级别，因此采用字典进行，没读一个数将其保存在字典当中

    def containsDuplicate(self, nums):
        dic={}
        for i in nums:
            if dic.get(i)==None:
                dic[i]=1
            else:
                return True
        return False

至此便可完成。

之后浏览大神解法，发现可以利用set，判断前后的长度是否一致即可

class Solution(object):
def containsDuplicate(self, nums):
    """
    :type nums: List[int]
    :rtype: bool
    """
    return len(nums) != len(set(nums))

引自https://leetcode.com/discuss/67164/one-line-solution-in-python