# Contains Duplicate

## Problem

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.

[Click Here](https://leetcode.com/problems/contains-duplicate/description/) to read the entire problem.

## Approach

Don’t get overwhelmed thinking about a number of data structures and procedures to solve this.  
It’s pretty straight forward.

We are given an array `nums` and we have to return `true` if any value appears at least twice and return `false` if it doesn’t - where every element appears only once.

We’re going to solve it using set.

When we convert the list into set, we eliminate the duplicate values. Okay, so now we have a list which may or may not contains duplicates and a set version of that contains only the unique values. How do we proceed from here?

just compare the length of the two data structures lol.

That’s it.

## Solution

```python
class Solution:
    def containsDuplicate(self, nums: List[int]) -> bool:
        if len(nums) == len(set(nums)):
            return False
        
        else:
            return True        
```

straight forward, simple and efficient.