Contains Duplicate II 找出数组中是否有重复元素，长度小于k

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.

出处：http://www.programcreek.com/2014/05/leetcode-contains-duplicate-ii-java/

/*public class Solution {

    public boolean containsNearbyDuplicate(int[] nums, int k) {

    HashMap<Integer, Integer> map = new HashMap<Integer, Integer>();

 

    for(int i=0; i<nums.length; i++){

        if(map.containsKey(nums[i])){

            int pre = map.get(nums[i]);

            if(i-pre<=k)

                return true;

        }

 

        map.put(nums[i], i);

    }

 

    return false;

}

}*/

 

public class Solution {

    public boolean containsNearbyDuplicate(int[] nums, int k) {

        if(nums==null || nums.length<2)  return false;

        int j=0;

        for(j=0;j<nums.length;j++){

            for(int i=j+1;i<nums.length && i<=j+k;i++){

                if (nums[i]==nums[j])   return true;

            }

        }

        //return j!=nums.length-1; 这个不行，超时不知道是不是是因为单纯的时间复杂度的问题

        return false;

    }

}