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 difference between i and j is at most k.

选择合适的数据结构。

public class Solution {

    public boolean containsNearbyDuplicate(int[] nums, int k) {
    Map<Integer,Integer> map=new HashMap<>();
        for(int i=0;i<nums.length;i++){
        Integer index=map.get(nums[i]);
        if(index!=null&&i-index<=k)
        return true;
        map.put(nums[i], i);
        }
        return false;
}
}