Leetcode15: Happy Number

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

class Solution {
public:
    bool isHappy(int n) {
        int count = 0;
        int sum = n;
        while(sum != 1)
        {
            n = sum;
            sum = 0;
            while(n)
            {
                sum += (n%10) * (n%10);
                n/=10;
            }
            count++;
            if(count == 100)
            return false;
        }
        return true;

    }
};

Leetcode15: Happy Number

原文：http://blog.csdn.net/u013089961/article/details/45197803