219. Contains Duplicate II

Problem Link

Description

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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

Solution

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Python3

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