Leetcode:happy number

Title Description:

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

Idea: The number that occurs in the process of calculating with a set record, if there is a duplicate number before getting 1, indicates that the number is not a happy number, otherwise it is happy number.

Code:

Class Solution{public:bool Ishappy (int n) {set<int> number_set;number_set.insert (n); while (true) {int m = 0;while ( n! = 0) {m = m + (n%10) * (n%10); n = N/10;} if (m = = 1) return true;else{if (Number_set.find (m)! = Number_set.end ()) return False;else{number_set.insert (m); n = m;}}}};

Leetcode:happy number