Happy Number
Explore the concept of happy numbers by implementing an algorithm that uses fast and slow pointers to detect cycles in the sum of squared digits. Learn to identify whether a number leads to 1, confirming it as happy, or falls into a loop, making it unhappy. This lesson helps you develop cycle detection techniques useful in coding interviews.
We'll cover the following...
Statement
Write an algorithm to determine if a number is a happy number.
We use the following process to check if a given number is a happy number:
- Starting with the given number , replace the number with the sum of the squares of its digits.
- Repeat the process until:
- The number equals , which will depict that the given number is a happy number.
- The number enters a cycle, which will depict that the given number is not a happy number.
Return TRUE if is a happy number, and FALSE if not.
Constraints
Examples
Test your understanding of the problem
Let’s take a moment to make sure we have correctly understood the problem. The quiz below helps us to check that we are solving precisely the right problem:
Happy Number
(True or False) 28 is a happy number.
True
False
Figure it out
We have a game for you to play: re-arrange the logical building blocks to develop a clearer understanding of how to solve this problem.
Try it yourself
Implement your solution in the following coding playground.
import java.util.*;public class Main{public static boolean isHappyNumber(int n) {// Replace this placeholder return statement with your codereturn false;}}