[LeetCode] 217. Contains Duplicate

Problem : https://leetcode.com/problems/contains-duplicate

Use hash table to find the duplicate. Time complexity = O ( N )

class Solution:
    def containsDuplicate(self, nums: List[int]) -> bool:
        counter = Counter(nums)
        return any( counter[n] >= 2 for n in nums )

Sort the input array first, then find the duplicate. Time complexity = O ( N * Log N )

class Solution:
    def containsDuplicate(self, nums: List[int]) -> bool:
        nums.sort()
        return any(nums[i-1] == nums[i] for i in range(1, len(nums)))

Edited on 05/02/2021. Update hash table approach.

Edited on 05/02/2021. Update locating if sorted array approach.