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.

Example 1:

Input: nums = [1,2,3,1], k = 3Output: true

Example 2:

Input: nums = [1,0,1,1], k = 1Output: true

Example 3:

Input: nums = [1,2,3,1,2,3], k = 2Output: false

难度：easy

题目：给定一整数数组和一整数K,找出是否存在两个不同的下标使用得nums[i]=nums[j]并且i与j之差的绝对值小于等于k.

思路：hashmap

Runtime: 9 ms, faster than 81.45% of Java online submissions for Contains Duplicate II.

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