LeetCode 217. Contains Duplicate



Given an array of integers, find if the array contains any duplicates.

Your function should return true if any value appears at least twice in the array, and it should return false if every element is distinct.

Example 1:

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

Example 2:

Input: [1,2,3,4]
Output: false

Example 3:

Input: [1,1,1,3,3,4,3,2,4,2]
Output: true


Simply use a hashmap to check if getting duplicates.

Python Solution

class Solution:
    def containsDuplicate(self, nums: List[int]) -> bool:
        counter = set()
        for num in nums:
            if num not in counter:
                return True
        return False
  • Time complexity : O(N).
  • Space complexity : O(N).

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