Contains Duplicate

• Source: https://neetcode.io/problems/duplicate-integer

Solution

class Solution:
	def hasDuplicate(nums: list[int]):
		occurred: set[int] = set()
		for n in nums:
			if n in occurred:
				return True
			occurred.insert(n)
		return False

• Time complexity: $O(n)$
• Space complexity: $O(n)$