Given an array of integers and an integerk, find out whether there are two distinct indicesiandjin the array such thatnums[i] = nums[j]and the difference betweeniandjis at mostk.

這道題還是很簡單的。沒啥可說的。直接用hashmap就可以做了，借助containsKey()，get()還有put()。

代碼如下。~

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