219. Contains Duplicate II

🟩 Easy

Question

Given an array of integers and an integer k, find out whether there are two distinct indices i and j in the array such that nums[i] = nums[j] and the absolute difference between i and j is at most k.

Example 1:

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

Example 2:

Input: nums = [1,0,1,1], k = 1
Output: true

Example 3:

Input: nums = [1,2,3,1,2,3], k = 2
Output: false

Complexity

• Time complexity: O(n)

• Space complexity: O(n)

Code

def containsNearbyDuplicate(self, nums: List[int], k: int) -> bool:
    table = dict()
    for i,num in enumerate(nums):
        if num in table and abs(i - table[num]) <= k: 
            return True
        table[num] = i
    return False