problem54

Solution of Project Euler's 54th problem using Java. Based on these rules.

Building

This project uses gradle as it's build tool. To run the project simply gradle run --args='poker.txt', to run tests: gradle test.

About the project

How the solution works

1. Parse each hand.

2. Compare hands, by finding a rule where player 1's hand matches, such as "Four of a Kind", if the other player's hand doesn't match, then that means that the first hand is valued higher. Otherwise, find out which hands' rank is higher.

3. Count all hands where player 1 wins.

Some additional explanations are located in javadocs of Rule and RuleSet.

What I like and do not like about my solution

What I like:

• It's not over-engineered (at least I think so), but at the same time the concerns of each rule are separated.

• It's quite functional

What I don't like:

• All the TODOs which were left unfinished. If I was willing to spend more time, I'd finish them.

• Error handling, or rather error reporting, could be improved, by:

  • checking that there is only 5 cards in a hand.
  • checking that each substring is only two characters long.
  • continue parsing other cards (possibly reporting more errors) even when parsing of a substring fails.

Which of the technologies or approaches were new to me

• JUnit & AssertJ.

  Although, I've used similar test frameworks before, it took some time to figure out the specifics of these.

• Java Streams

  Coming form such languages as Haskell, Rust, Scala, Java's Stream feels somewhat esoteric. Having the solution in your head, but unable to translate it to Java, at times, was a bit frustrating.