LeetCode:Contains Duplicate II

Problems:

 Given an array of integers and an integer k, find out whether there 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. 

解法一：leetcode的测试用例不全                                                                                                                                                                                                                                                                                                                                                                                                                                    

解法一：hashmap用来记录已出现的索引数

class Solution {
public:
    bool containsNearbyDuplicate(vector<int>& nums, int k) {
        if(nums.size()==0|| k==0) return false;
        
        unordered_map<int,int> maping;
        
        for(int i=0;i<nums.size();i++)
        {   
            if(maping.find(nums[i])!=maping.end() && i-maping[nums[i]]<=k)
               return true;
            else
               maping[nums[i]]=i;
        }
        return false;
    }
};