217. Contains Duplicate (python)

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.
题意：判断数组是否有重复的数，如果有元素出现不止一次返回true,否则返回false
方法一：hash表
Runtime: 82 ms
方法二：set集合，不重复的集合
Runtime: 58 ms

class Solution(object):
    def containsDuplicate(self, nums):
        dict={}
        for i in range(len(nums)):
            if nums[i] in dict:
                return True
            else:
                dict[nums[i]]=0
        return False

class Solution(object):
    def containsDuplicate(self, nums):
        return len(nums) != len(set(nums))