197 lines
5.8 KiB
Markdown
197 lines
5.8 KiB
Markdown
## To build:
|
|
|
|
``` <!---sh-->
|
|
make
|
|
```
|
|
|
|
|
|
## To use:
|
|
|
|
``` <!---sh-->
|
|
./robison
|
|
```
|
|
|
|
|
|
## Judges' remarks:
|
|
|
|
The program plays almost always reasonably, but does not always detect
|
|
illegal moves. Try "9 1" as your first move, then "13 2". Also it
|
|
tends to think for quite a while in the beginning of a game. It is
|
|
also smart enough to give up by making a losing move at the end of
|
|
a game when its position is hopeless.
|
|
|
|
Unfortunately, due to the contest rules, we're unable to grant the
|
|
author a patent he applied for. :-)
|
|
|
|
|
|
## Author's remarks:
|
|
|
|
### TITLE OF INVENTION
|
|
|
|
Highly Compressed Program for Playing Hygienic Checkers
|
|
|
|
|
|
### FIELD OF INVENTION
|
|
|
|
The present invention generally relates to
|
|
[Checkers](https://en.wikipedia.org/wiki/Checkers).
|
|
|
|
|
|
### BACKGROUND OF THE INVENTION
|
|
|
|
Within the field of [Checkers](https://en.wikipedia.org/wiki/Checkers), the
|
|
problem of finding a hygienic opponent is difficult, as good opponents are
|
|
peculiar to the tavern habitat of cracker-barrels, pot-belly stoves, tobacco,
|
|
and spittoons.
|
|
|
|
|
|
### BRIEF SUMMARY OF THE INVENTION
|
|
|
|
The present invention plays [Checkers](https://en.wikipedia.org/wiki/Checkers)
|
|
without spitting.
|
|
|
|
|
|
### BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE INVENTION
|
|
|
|
FIG. 1 shows a numbering of positions.
|
|
|
|
FIG. 2 shows a numbering of directions.
|
|
|
|
FIG. 3 shows a sample board.
|
|
|
|
FIG. 4 shows a method in accordance with the present invention.
|
|
|
|
|
|
### DETAILED DESCRIPTION OF THE INVENTION
|
|
|
|
Operator plays Black (`x`); the program plays White (`o`). Said Black goes first.
|
|
On operator's turn, said program requests a position and direction. FIG. 1 shows
|
|
the numbering of the squares. FIG. 2 shows the numbering of directions. As per
|
|
standard rules, if one or more jumps are possible, one of the jumps must be
|
|
taken in preference to other moves. Said operator enters the numbers for the
|
|
position and direction. If after jumping over a piece, another jump is
|
|
possible, and said piece did not become a king after said jump, standard rules
|
|
require that another jump be taken. In said case, said program requests a
|
|
direction only in which to continue jumping from the present position. Kings
|
|
are denoted by upper case. FIG. 3 shows a sample board. There is a black king
|
|
(`X`) on square 30 and a red king (`O`) on square 2. The numbers on the right are
|
|
the numbers of the rightmost square in each row.
|
|
|
|
A player loses if they cannot make a legal move. Said loss is trivially
|
|
true if player loses all of his/her pieces. The present invention announces
|
|
said loser.
|
|
|
|
FIG. 4 shows a C program in accordance with the present invention. Control flow
|
|
is straightforward: control enters routine `main()`, executes a plurality of
|
|
statements, and exits via a `return` statement. FIG. 4 presumes that type `int`
|
|
is `32 bits` and `short` is `16 bits`, which are essential to the preferred
|
|
embodiment of the invention. FIG. 4 also presumes that the host computer uses
|
|
ASCII encoding for characters. It should be obvious that practitioners skilled
|
|
in the art of C programming can remove said limitations.
|
|
|
|
The disclosure here describes a particular embodiment of the present invention,
|
|
and other embodiments within the spirit of this disclosure are possible, as well
|
|
as consumption of spirits while playing.
|
|
|
|
|
|
### CLAIMS
|
|
|
|
I claim, by letters patently absurd:
|
|
|
|
1. A method for playing checkers on a computer-based system, where said
|
|
method's source code fits into 1536 countable bytes of source code,
|
|
where a byte is countable if
|
|
* it is not whitespace and
|
|
* it is not a '`{`', '`}`', or '`;`' immediately followed by whitespace.
|
|
|
|
2. The method of claim 1, further comprising a method of alpha-beta pruning
|
|
that exploits the zero-sum nature of the game to unify alpha
|
|
and beta cuts.
|
|
|
|
3. The method of claim 1, further comprising the step of formatting the
|
|
source code with short lines, in order to impress the manager with
|
|
high productivity, when measured in lines of code.
|
|
|
|
4. The method of claim 3, further comprising the step for telling the
|
|
skeptical manager that this is the well-known technique of
|
|
"linear programming".
|
|
|
|
5. The method of claim 1, where `~-` and `-~` replace the obvious arithmetic
|
|
operations.
|
|
|
|
6. The method of claim 1, further comprising a method where
|
|
* strings are encrypted in a manner suitable as C strings, and
|
|
* 7-bit ASCII characters with uniform distribution are maximally packed
|
|
subject to the restriction that each byte is not countable
|
|
|
|
7. A method for a computer-based system that uses a single shared code
|
|
sequence to either sum a plurality of bits in an N-bit word or reverses
|
|
them, in lg(N) time, depending upon a parameter.
|
|
|
|
|
|
### DRAWINGS
|
|
|
|
#### FIG 1.
|
|
|
|
```
|
|
+--+--+--+--+--+--+--+--+
|
|
|32| |31| |30| |29| |
|
|
+--+--+--+--+--+--+--+--+
|
|
| |28| |27| |26| |25|
|
|
+--+--+--+--+--+--+--+--+
|
|
|24| |23| |22| |21| |
|
|
+--+--+--+--+--+--+--+--+
|
|
| |20| |19| |18| |17|
|
|
+--+--+--+--+--+--+--+--+
|
|
|16| |15| |14| |13| |
|
|
+--+--+--+--+--+--+--+--+
|
|
| |12| |11| |10| | 9|
|
|
+--+--+--+--+--+--+--+--+
|
|
| 8| | 7| | 6| | 5| |
|
|
+--+--+--+--+--+--+--+--+
|
|
| | 4| | 3| | 2| | 1|
|
|
+--+--+--+--+--+--+--+--+
|
|
```
|
|
|
|
#### FIG. 2.
|
|
|
|
```
|
|
1 0
|
|
\ /
|
|
.
|
|
/ \
|
|
3 2
|
|
```
|
|
|
|
#### FIG. 3.
|
|
|
|
```
|
|
o o X . 29
|
|
o . . . 25
|
|
o . . o 21
|
|
. o . o 17
|
|
x . . . 13
|
|
. . x . 9
|
|
x x . . 5
|
|
x x O x 1
|
|
```
|
|
|
|
#### FIG. 4
|
|
|
|
[See attached listing.]
|
|
|
|
|
|
<!--
|
|
|
|
Copyright © 1984-2024 by Landon Curt Noll. All Rights Reserved.
|
|
|
|
You are free to share and adapt this file under the terms of this license:
|
|
|
|
Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)
|
|
|
|
For more information, see:
|
|
|
|
https://creativecommons.org/licenses/by-sa/4.0/
|
|
|
|
-->
|