From: Ruby Quiz Date: 2006-09-01T22:01:41+09:00 Subject: [QUIZ] Happy Numbers (#93) The three rules of Ruby Quiz: 1. Please do not post any solutions or spoiler discussion for this quiz until 48 hours have passed from the time on this message. 2. Support Ruby Quiz by submitting ideas as often as you can: http://www.rubyquiz.com/ 3. Enjoy! Suggestion: A [QUIZ] in the subject of emails about the problem helps everyone on Ruby Talk follow the discussion. Please reply to the original quiz message, if you can. -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= by Shane Emmons Write a program that tells whether a given integer is happy. A happy number is found using the following process: Take the sum of the squares of its digits, and continue iterating this process until it yields 1, or produces an infinite loop. For example the number 7: 7^2 = 49 4^2 + 9^2 = 97 9^2 + 7^2 = 130 1^2 + 3^2 + 0^2 = 10 1^2 + 0^2 = 1 If a number is not happy than it is obviously unhappy. Now that you have this program, what is the largest happy number you can find? What is the happiest number between 1 and 1,000,000. I define the happiest number as the smallest number that finds the most other happy numbers with it, i.e. 7 found four other numbers (49, 97, 130, and 10) making it a rank 4 in happiness. If you find all these examples trivial, write you program so that it will find happy numbers in other bases such as base 2 or 16. From there you can extend the program so that it finds happy bases (other than 2 and 4). A happy bases is a base where all numbers are happy. Good luck.