> For the complete documentation index, see [llms.txt](https://garylai.gitbook.io/algorithm-and-data-structure/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://garylai.gitbook.io/algorithm-and-data-structure/problems/hash-table/contains-duplicate.md).

# 217. Contains Duplicate

[217. Contains Duplicate](https://leetcode.com/problems/contains-duplicate/)

```python
class Solution:
    def containsDuplicate(self, nums: List[int]) -> bool:
        S = set(nums)
        return len(S) != len(nums)
```