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.

和http://www.jianshu.com/p/993639a376f0 差不多多了一个条件。

class Solution {
    public boolean containsNearbyDuplicate(int[] nums, int k) {
        HashMap map = new HashMap<>();
        for(int i = 0 ;i