217. Contains Duplicate

https://neetcode.io/roadmap

NeetCode.io

 

Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct.

class Solution(object):
    def containsDuplicate(self, nums):
        setCollection = set()
        for num in nums:
            if num in setCollection:
                return True
            setCollection.add(num)
        return False

not(len(nums)==len(set(nums)))