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| 1.4.0 | Jun 18, 2024 |
|---|---|
| 1.3.0 | Apr 12, 2024 |
| 1.2.0 | Apr 11, 2024 |
| 1.1.0 | Apr 11, 2024 |
| 1.0.0 | Apr 10, 2024 |
#508 in Data structures
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A Lightweight Library for Efficient Card Representation
The StandardCard library provides a programmer-friendly way to represent a standard deck of 52 cards.
It prioritizes both fast access to card information and minimal storage footprint, making it ideal for various game development or card manipulation tasks.
Card definition
A card is an integer is made up of four bytes. The high-order bytes are used to hold the rank bit pattern, whereas the low-order bytes hold the suit/rank/prime value of the card.
| xxxAKQJT | 98765432 | cdhsrrrr | sspppppp |
|---|---|---|---|
| xxxbbbbb | bbbbbbbb | cdhsrrrr | sspppppp |
Where
| Key | Definition |
|---|---|
| p | Prime number of rank |
| s | Suit of card (clubs=00, diamonds=01, hearts=10, spades=11) |
| r | Rank of card |
| cdhs | bit turned on depending on suit of card (spades=0001,...,clubs=1000) |
| b | bit turned on depending on rank of card |
As an example, the Five of Hearts (5h) would be represented as
| xxxAKQJT | 98765432 | cdhsrrrr | sspppppp | |
|---|---|---|---|---|
| 00000000 | 00001000 | 00100011 | 01000111 | = 0x00082347 = 533319 |
More information about the card is presented in a table below
| 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | J | Q | K | A | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Ranks | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
| Primes | 2 | 3 | 5 | 7 | 11 | 13 | 17 | 19 | 23 | 29 | 31 | 37 | 41 |
The 52-card deck
Building on the previous card definition, let's look at the value table for a standard 52-card deck
| 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | J | Q | K | A | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clubs | 98306 | 164099 | 295429 | 557831 | 1082379 | 2131213 | 4228625 | 8423187 | 16812055 | 33589533 | 67144223 | 134253349 | 268471337 |
| Diamonds | 81986 | 147779 | 279109 | 541511 | 1066059 | 2114893 | 4212305 | 8406867 | 16795735 | 33573213 | 67127903 | 134237029 | 268455017 |
| Hearts | 73858 | 139651 | 270981 | 533383 | 1057931 | 2106765 | 4204177 | 8398739 | 16787607 | 33565085 | 67119775 | 134228901 | 268446889 |
| Spades | 69826 | 135619 | 266949 | 529351 | 1053899 | 2102733 | 4200145 | 8394707 | 16783575 | 33561053 | 67115743 | 134224869 | 268442857 |
Benefits
-
Minimal Memory Usage: data structures can represent all card information with a single identifier. -
Faster Lookups: Retrieving card information becomes a constant-time operation due to the use of bit-wise operator.