# [202. Happy Number](https://leetcode.com/problems/happy-number/) ## 题目 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 1: ```c Input: 19 Output: true Explanation: 12 + 92 = 82 82 + 22 = 68 62 + 82 = 100 12 + 02 + 02 = 1 ``` ## 题目大意 判断一个数字是否是“快乐数字”,“快乐数字”的定义是,不断的把这个数字的每个数字的平方和加起来,反复的加,最终如果能有结果是 1,则是“快乐数字”,如果不能得到一,出现了循环,则输出 false。 ## 解题思路 按照题意要求做即可。