[Leetcode] Happy number

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 and replace the number by the Sum of the squares of its digits, and repeat the process until the number equals 1 (where it would stay), or it loops Endl essly in a cycle which does not include 1. Those numbers for which this process ends in 1 is happy numbers.

Example: is a happy number

• 12 + 92 = 82
• 82 + 22 = 68
• 62 + 82 = 100
• 12 + 02 + 02 = 1

Credits:
Special thanks to @mithmatt and @ts for adding the problem and creating all test cases.

Problem Solving Ideas:

Simulation method can be. Records all computed n with a set, returns False if the repetition (loop) occurs, and returns True if N is 1;

Class Solution {public:    bool Ishappy (int n) {        if (n<=0) {            return false;        }        Set<int> Checkednumber;        while (n!=1) {            checkednumber.insert (n);            int tempn=0;            while (n!=0) {                int num=n%10;                N=N/10;                Tempn+=num*num;            }            N=TEMPN;            if (Checkednumber.find (n)!=checkednumber.end ()) {                return false;            }        }        return true;    }};

[Leetcode] Happy number