LeetCode 202. Happy Number

非常巧，前后做了两次，写的代码思路、甚至是空行都是一模一样的...

代码：

class Solution 
{
public:
    bool isHappy(int n) 
    {
    	if (int_set.find(n) != int_set.end())
    	{
    		return false;
    	}
    	int_set.insert(n);

    	int new_num = 0;
    	for ( ; n != 0; n /= 10)
    	{
    		new_num += ((n % 10) * (n % 10));
    	}

    	return new_num==1 || isHappy(new_num);
    }

private:
	unordered_set<int> int_set;
};

LeetCode 202. Happy Number

原文：http://blog.csdn.net/stephen_wong/article/details/46591315