• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
Sign in to follow this  
Followers 0

Find poker combination in a set of cards

6 posts in this topic


I'm looking for an algorithm that finds the poker combinations (specifically straight, flush, full house, four of a kind, and straight flush) in a set of 13 cards. The most naive implementations is to check each element in a power set of the cards (hence 1287 possible combinations), but experience tells me there is always a better way.


Share this post

Link to post
Share on other sites
For such a limited set of rules as poker hands, I would not extract 5-card hands and search for winning hands but search for hands in the entire set of cards.

Sort the cards by face value and start with the most valuable hand and search for it:[list=1]
[*]Is there any sequence of 5 consecutive face values of the same suite?
[*]Are there four cards of the same face value?
[*]Are there three cards of one face value and two cards of another face value?
[*]Are there five cards of the same suite?
[*]... and so on.
Sorting the cards by decreasing face value makes it easy to find sequences of identical (for a 4-of-a-kind) or consecutive (for a straight) values.

Share this post

Link to post
Share on other sites
Brother Bob's approach is the best and traditionally used one, also in the case when joker cards are present. Even though the logic needs to be carefully thought out, it will beat a naive "check all 5-subsets of 13 cards".

Share this post

Link to post
Share on other sites
Brother Bob's idea is generally right, but there is a representation of the hand that allows for much faster code: Store each suit as a 13-bit integer, indicating which cards are present in the hand.

Since 2^13 = 8192 is a reasonably small number, you can aid the algorithm by using a few precomputed tables, with things like what is the highest bit set in a word, or what is the highest bit of a group of at least 5 consecutive bits (to detect straights).

The code would look something like this:
[code]struct Hand {
unsigned short suit[4];
unsigned evaluate() const;
unsigned Hand::evaluate() const {
// Straigth flush
unsigned highest_straight_flush = 0u;
for (int i=0; i<4; ++i) {
unsigned value = highest_card_of_straight_table[suit[i]];
if (value > highest_straight_flush)
highest_straight_flush = value;
if (highest_straight_flush != 0u)
return STRAIGHT_FLUSH | heighest_straight_flush;
// 4 of a kind
unsigned short all_suits = ~0u;
for (int i=0; i<4; ++i)
all_suits &= suit[i];
if (all_suits != 0)
return FOUR_OF_A_KIND | highest_card_table[all_suits];
// ...

Share this post

Link to post
Share on other sites
[quote name='Glass_Knife' timestamp='1349887736' post='4988769']
Is this for open faced Chinese poker?
No, it's for this: [url="http://www.gamedev.net/topic/632575-ai-for-a-simple-shedding-card-game/"]http://www.gamedev.n...ding-card-game/[/url]

I believe this is logically complete, but is still a bit naive:

look for cards with the same face value, keep only one of them in the temporary deck
sort, look for cards with consecutive face values
5+n consecutive cards = n+1 straights (so far)
substitute cards in the straight with the same face value, add each to list

sort the cards by suite,
5+n cards with the same suite = n+1 flushes

full house
sort cards, look for cards that occur >= 3. if none, quit
look for cards that occur in pairs.
C(n1,3) . C(n2,2) for faces that occur >= 3.
C(n,3) . pairs

4 of a kind
sort cards, look for 4 same face values
5th card any other card

straight flush
use previously found straights and flushes, avoid duplicate combinations


I'm still looking at alvaro's code. Edited by mudslinger

Share this post

Link to post
Share on other sites
Have you looked at the ideas and algorithms at


I have ported the two-plus-two evaluator for Java to do hand matchups,
and it worked very well, although the 128 Mb table was a little ridiculous.

Between the ideas already presented, and all the free code,
I'd say you're on your way! Edited by Glass_Knife
bad grammer

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  
Followers 0