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Leetcode219-containsDuplicateII

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Solution Report of LeetCode Acceptted

Description

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

Example 1:

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

Example 2:
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Input: nums = [1,0,1,1], k = 1
Output: true

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

Solution

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class Solution {
    public boolean containsNearbyDuplicate(int[] nums, int k) {
        if (nums == null || nums.length == 0) return false;
        HashSet<Integer> set = new HashSet<>();
        
        for (int i = 0; i < nums.length; i++){
            if (i > k) set.remove(nums[i - k - 1]);
            if (!set.add(nums[i])) return true;
        }
        return false;
    }
}