【LeetCode】202 - 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

Solution: 辅助函数；循环计算每位数字的平方和，直到出现结果为1(返回true)或者重复(返回false)

 class Solution {

 public:

     bool isHappy(int n) {

         map<int,bool> m;

         int ret=sum(n);

         while(ret!=){

             if(m[ret]==true)return false;

             m[ret]=true;

             ret=sum(ret);

         }

         return true;

     }

     int sum(int n){

         int ret=;

         while(n){

             ret += (n%)*(n%);   //不支持（n%10)^2

             n /= ;

         }

         return ret;

     }

 };

巴特西

【LeetCode】202 - Happy Number

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