This is my Ruby translation to Peter Norvig's solution to When is Cheryl's Birthday problem.

When is Cheryl's Birthday?

1. Albert and Bernard just became friends with Cheryl, and they want to know when her birthday is. Cheryl gave them a list of 10 possible dates:

       May 15     May 16     May 19
      June 17    June 18
      July 14    July 16
    August 14  August 15  August 17
   

2. Cheryl then tells Albert and Bernard separately the month and the day of the birthday respectively.

3. Albert: I don't know when Cheryl's birthday is, but I know that Bernard does not know too.

4. Bernard: At first I don't know when Cheryl's birthday is, but I know now.

5. Albert: Then I also know when Cheryl's birthday is.

6. So when is Cheryl's birthday?

View Peter Norvig's solution translate in Ruby:

• Create abstraction for cheryl's possible dates
• Cheryl tells part of birthday
• Person knows birthday if possible date only one
• Statement 3 - Albert: I don't know when Cheryl's birthday is, but I know that Bernard does not know too
• Statement 4 - Bernard: At first I don't know when Cheryl's birthday is, but I know now
• Statement 5 - Albert: Then I also know when Cheryl's birthday is
• So when is Cheryl's birthday?

Credits

See norvig/pytudes - Python programs to practice or demonstrate skills, it's gold.