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219. Contains Duplicate II

Array Hash Table Sliding Window

Problem - Contains Duplicate II

Easy

Given an integer array nums and an integer k, return true if there are two distinct indices i and j in the array such that nums[i] == nums[j] and abs(i - j) <= 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

 

Constraints:

  • 1 <= nums.length <= 105
  • -109 <= nums[i] <= 109
  • 0 <= k <= 105

Solutions

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class Solution:
    def containsNearbyDuplicate(self, nums: List[int], k: int) -> bool:
        hash_table = {}
        for i, num in enumerate(nums):
            if num in hash_table and i - hash_table[num] <= k:
                return True
            hash_table[num] = i
        return False

Submission Stats:

  • Runtime: 30 ms (61.24%)
  • Memory: 36.7 MB (38.90%)