LeetCode:Happy Number

浏览数：16 / 时间：2015年06月11日

题目描述：

Write an algorithm to determine if a number is "happy".

A happy number is a number defined by the following process: Starting with any positive integer, replace the number by the sum of the squares of its digits, and repeat the process until the number equals 1 (where it will stay), or it loops endlessly in a cycle which does not include 1. Those numbers for which this process ends in 1 are happy numbers.

Example: 19 is a happy number

12 + 92 = 82
82 + 22 = 68
62 + 82 = 100
12 + 02 + 02 = 1

思路：用一个set记录计算的过程中出现的数，如果在得到1之前有重复的数出现，则表示这个数不是一个happy数，否则就是happy数。

代码:

class Solution
{
	public:
		bool isHappy(int n)
		{
			set<int> number_set;
			number_set.insert(n);
			while(true)
			{
				int m = 0;
				while(n != 0)
				{
					m = m + (n%10) * (n%10);
					n = n/10;
				}
				if(m == 1)
					return true;
				else
				{
					if(number_set.find(m) != number_set.end())
						return false;
					else
					{
						number_set.insert(m);
						n = m;
					}
				}
			}
		}
};

郑重声明：本站内容如果来自互联网及其他传播媒体，其版权均属原媒体及文章作者所有。转载目的在于传递更多信息及用于网络分享，并不代表本站赞同其观点和对其真实性负责，也不构成任何其他建议。

LeetCode:Happy Number