[LeetCode]219 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 absolute difference
between i and j is
at most k.

Simple
Java solution

public boolean containsNearbyDuplicate(int[] nums, int k) {
Set<Integer> set = new HashSet<Integer>();
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;
}