Package g0201_0300.s0202_happy_number

Class Solution

  • All Implemented Interfaces:
    
public final class Solution

    202 - Happy Number\.

    Easy

    Write an algorithm to determine if a number n 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.

    • 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.

    Return true if n is a happy number, and false if not.

    Example 1:

    Input: n = 19

    Output: true

    Explanation: 1<sup>2</sup> + 9<sup>2</sup> = 82 8<sup>2</sup> + 2<sup>2</sup> = 68 6<sup>2</sup> + 8<sup>2</sup> = 100 1<sup>2</sup> + 0<sup>2</sup> + 0<sup>2</sup> = 1

    Example 2:

    Input: n = 2

    Output: false

    Constraints:

    • <code>1 <= n <= 2<sup>31</sup> - 1</code>

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description

    • Field Summary

      Fields 
      Modifier and Type Field Description

    • Constructor Summary

      Constructors 
      Constructor Description
      Solution()

    • Enum Constant Summary

      Enum Constants 
      Enum Constant Description

    • Method Summary

      Modifier and Type Method Description
      final Boolean isHappy(Integer n)

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait