LeetCode *** 219. Contains Duplicate II

题目：

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.

分析：

i与j相差是k，那么意味着要考察k+1个数的大小。。我的方法太蠢了。。。

代码：

class Solution {
public:
    bool containsNearbyDuplicate(vector<int>& nums, int k) {
        
        if(k<1)return false;
        int size=nums.size();
        
        set<int> mySet;
        int i;
        
        for(i=0;i<=k&&i<size;++i)
            mySet.insert(nums[i]);
            
        if(i==size){
            if(mySet.size()<size)return true;
            else return false;
        }
        
        if(mySet.size()<=k)return true;
        
        
        
        for(int i=k+1;i<size;++i){
            mySet.erase(mySet.find(nums[i-k-1]));
            mySet.insert(nums[i]);
            if(mySet.size()<=k)return true;
        }
        
        return false;
        
    }
};