217. Contains Duplicate （easy）

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.

Example 1:

Input: [1,2,3,1]
Output: true

Example 2:

Input: [1,2,3,4]
Output: false

Example 3:

Input: [1,1,1,3,3,4,3,2,4,2]
Output: true

這道題存在超大的邊界測試-24500～29999，所以如果遍歷會超時

思路

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

Runtime: 48 ms, faster than 80.16% of Python3 

語句可以精簡如下

  return len(set(nums)) < len(nums)