Contains Duplicate

01 · Question

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

Example:

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

02 · Solution

Reference solution

1def containsDuplicate(nums: List[int]) -> bool:
2    seen = set()
3    
4    for x in nums:
5        if x in seen:
6            return True
7        seen.add(x)
8        
9    return False

Two Sum

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