[leetcode]Contains duplicate ii

public class Solution { public boolean containsNearbyDuplicate(int[] nums, int k) { if (nums.length <= 1 || k < 1) return false; HashMap lookup = new HashMap(); for (int i = 0; i < nums.length; i++){ if (lookup.containsKey(nums[i])&&(i - lookup.get(nums[i]).intValue() <= k)){ return true; } lookup.put(nums[i], i); } return false; } }