Leetcode Note--202happy number

1 Topic 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:19 is a happy number

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

Link Address: https://leetcode.com/problems/happy-number/

2 Solutions

The Java code is as follows:

public class Solution {public    boolean ishappy (int n) {        int result = 0; arraylist<integer> list = new arraylist<integer> ();    Boolean islucky = false;    if (n <= 0) {return islucky;} while (true) {int sum = 0;int num = n;while (num > 0) {int temp = Num%10;num = (num-temp)/10;sum = SUM  + temp * t EMP;} result = Sum;if (Result ==1) {islucky = True;break;} else if (list.contains (Result)) {islucky = False;break;} else {n = result;list.add (result);}} return islucky;}    }

　　

Leetcode Note--202happy number