Leetcode: Contains Duplicate II

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 difference between i and j is at most k.

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