Contains Duplicates

Problem

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.

Thought Process

• Just use a set or dictionary to check if the number already exists

Solution

class Solution:
    def containsNearbyDuplicate(self, nums: List[int], k: int) -> bool:
        d = {}
        
        for i in range(len(nums)):
            if nums[i] in d:
                if abs(i - d[nums[i]]) <= k:
                    return True
            d[nums[i]] = i
        return False
                

Time Complexity

• Time: O(n)

• Space: O(n)