# [Contains Duplicate](https://leetcode.com/problems/contains-duplicate/)
###### tags: `Leetcode`, `Easy`, `Arrays and Hashing`

## Approach
* Initialize a hashset
* Iterate through list and check if number is present in the hashset
* If present, return False

## Asymptotic Analysis
### Time Complexity: **O(n)**
### Space Complexity: **O(n)**

## Code

class Solution:
    def containsDuplicate(self, nums: List[int]) -> bool:
        # initialize a hashset
        numHash = set()
        # add elements to hashset
        for num in nums:
            if num in numHash: return True
            numHash.add(num)
        return False