Re:What I learned from my first C coding challenge
by T-hawk on Tuesday September 04, 2012 @03:15PM
(#4476067)
Here's a similar case: Ranking of poker hands. That can involve many of the same steps, like sorting a small list of inputs (5 or 7 cards) into a normalized configuration (three-of-a-kind is represented as AAABC where B > C) and taking a hash to memoize the result. And you sure might want that in a tight inner loop if you're writing a poker simulator or AI where you want to crunch a few billion iterations.
[ Parent
| on HN ]
Re:What I learned from my first C coding challenge
by jefffoster on Tuesday September 04, 2012 @04:26PM
(#4476368)
Actually, for a poker hand evaluator the last thing you want to do is sort the hands. There's a small enough number of unique card combinations that you can arrange it so that you look up in pre-computed tables more often than not.
One clever trick is assigning a prime to each card value. By multiplying the values together you get a unique number representing each hand without needing to sort.
There's a great description of an algorithm at http://www.suffecool.net/poker/evaluator.html.