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) {            Map<Integer,Integer> map = new HashMap<>();            for (int i=0;i<nums.length;i++)            {                if(!map.containsKey(nums[i]))                    map.put(nums[i],i);                else                {                    if(Math.abs(map.get(nums[i])-i)<=k)                        return true;                    else                        map.put(nums[i],i);                }            }            return false;        }}