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