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.

solution:

public class Solution {
    public boolean containsNearbyDuplicate(int[] nums, int k) {
        HashMap<Integer,Integer> map = new HashMap();
        for(int i = 0 ; i < nums.length; i++){
            if(map.containsKey(nums[i])){
                if(i - map.get(nums[i]) <= k) return true;
                else map.put(nums[i], i);
            }
            else{
                map.put(nums[i], i);
            }
        } 
        return false;
    }
}