217. Contains Duplicate

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.

Example 1:

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

Example 2:

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

Example 3:

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

Constraints:

• 1 <= nums.length <= 10<sup>5</sup>

• -10<sup>9</sup> <= nums[i] <= 10<sup>9</sup>

Solution:

class Solution:
    def containsDuplicate(self, nums: List[int]) -> bool:
        hashset = set()
        for n in nums:
           if n in hashset:
               return True
           hashset.add(n)
        return False