202. Happy number "Leetcode" Java,hashset, algorithm

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 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:19 is a happy number

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

Test instructions

Write an algorithm to determine whether a number is "happy".
A pleasant number is a number defined by the following procedure: Starting with any positive integer, replacing the number with the square of its number, repeating the process until the number equals 1 (where it will stay), or looping in a loop that does not include 1. This process with a number of 1 endings is the happy number.
Example: 19 is a happy number.

1  Public classSolution {2     Private intGethappynumber (intN) {3         intSum=0;4          while(n!=0){5sum+= (n%10) * (n%10);6N=n/10;7         }8         returnsum;9     }Ten      Public BooleanIshappy (intN) { OneHashset<integer> hash=NewHashset<integer>(); A          while(n!=1){ -             if(Hash.contains (n)) -                 return false; the             Else{ - Hash.add (n); -n=gethappynumber (n); -             } +         } -         return true; +     } A}

202. Happy number "Leetcode" Java,hashset, algorithm