10-217. Contains Duplicate

题目描述：

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

代码实现：

1 class Solution:
2     def containsDuplicate(self, nums) -> bool:
3         return len(nums) != len(set(nums))

分析：

利用python的set()函数，可以非常简单地判断有无重复元素：set()函数会自动把重复的元素去掉（集合中不能包含重复的元素！）。