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.

样例

19 is a happy number

思路:

1、把数字按位拆开,计算平方和,如果平方和是1那么这个数字是满足要求的

2、如果算出的数字以前已经出现过,则是一个循环无解的数

 

发表评论