219.Contains Duplicate II

Posted 2020-08-09 Machelsky

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.

思路：hashmap很简单。

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