LeetCode:Happy Number

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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

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;
					}
				}
			}
		}
};

LeetCode:Happy Number

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原文地址：http://blog.csdn.net/yao_wust/article/details/45645529