題目：

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

       定義一種快樂數，就是說對於某一個正整數，如果對其各個位上的數字分別平方，然後再加起來得到一個新的數字，再進行同樣的操作，如果最終結果變成了1，則說明是快樂數，如果一直迴圈但不是1的話，就不是快樂數。數字19就是一個快樂數。