Format/typo check 1993/ejb

This includes updates to the patience.md file. The hanoi.md did not
require any changes.
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Cody Boone Ferguson committed 2023-11-09 11:00:08 -08:00
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@@ -54,8 +54,8 @@ text description of how to solve the puzzle.
For the patience puzzle, the output is a sequence binary codes representing
successive states of the puzzle. The rightmost digit represents the first ring.
A "1" means the ring is on the U; a "0" means it is off the U. The program
prints the word "Invalid" in response to illegal command line parameters.
A `1` means the ring is on the `U`; a `0` means it is off the `U`. The program
prints the word `"Invalid"` in response to illegal command line parameters.
### Motivation
@@ -67,14 +67,14 @@ This program serves to show that counting semicolons will not
always provide a meaningful measure of code size. This is
especially true in this program where the number of semicolons
itself is ambiguous. Does it have two or three? In addition, the
only "C" keyword this program uses besides type names and
only C keyword this program uses besides type names and
qualifiers is `return`, and the only function defined in the code
is `main`. The level of complexity of the program without multiple
is `main()`. The level of complexity of the program without multiple
semicolons, statements, and functions is achieved by abusing C
operators, especially the comma operator. Considerable use of `||`,
`&&`, and `? :` helps too. In addition, main is called recursively.
The NULL pointer that terminates argv is used to pass additional
information into main. Even though the algorithms used by this
`&&`, and `?:` helps too. In addition, `main()` is called recursively.
The NULL pointer that terminates `argv` is used to pass additional
information into `main()`. Even though the algorithms used by this
code are simple, this program is still hard to follow even when
indented properly. (It is pretty hard to indent this code
reasonably, however.)
@@ -85,7 +85,7 @@ preprocessor at all. The only functions it uses are `atoi()`, `malloc()`,
`memset()`, `printf()`, and `puts()`. It does, however, require that the
architecture it runs on have bytes that are at least eight bits long and
pointers that are at least four bytes long. In addition, it requires an ANSI
compiler since it uses "signed char" and ANSI-style function declarations.
compiler since it uses `signed char` and ANSI-style function declarations.
## Copyright and CC BY-SA 4.0 License:
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@@ -21,38 +21,39 @@ ring at the end of the rod to its right. The only rod free
of this restriction is the rightmost rod. What has been
described so far is one of the two components of the puzzle.
The other component is another iron rod shaped like a U.
The U is as long from the tips to the base as the original
piece of iron with the holes in it. The ends of the U are
The other component is another iron rod shaped like a `U`.
The `U` is as long from the tips to the base as the original
piece of iron with the holes in it. The ends of the `U` are
looped around another ring of about five centimeters in
diameter. In the puzzle's initial configuration, the U is
diameter. In the puzzle's initial configuration, the `U` is
placed through the rings so that it is held in place by the
iron rods. Imagine starting with the U piece before the
iron loop is placed at the end. Slide the legs of the U
iron rods. Imagine starting with the `U` piece before the
iron loop is placed at the end. Slide the legs of the `U`
through the loops so that the iron rods securing the loops
to the metal strip go up the center of the U. Placing the
final ring at the ends of the U prevents it from coming out.
The object of the puzzle is to free the U-shaped piece from
to the metal strip go up the center of the `U`. Placing the
final ring at the ends of the `U` prevents it from coming out.
The object of the puzzle is to free the `U`-shaped piece from
the other piece.
The following illustration (sideways) shows a three-ring
case of this puzzle. If you look carefully, you can see
that the first ring could be lifted over the edge of the U
and slid down through the center of the U, thereby freeing
the U from the first iron rod. The second ring can also be
that the first ring could be lifted over the edge of the `U`
and slid down through the center of the `U`, thereby freeing
the `U` from the first iron rod. The second ring can also be
freed in the initial configuration since it is already over
the rod for the first ring. The third ring cannot be moved,
however, since it is blocked by the iron rod two which the
however, since it is blocked by the iron rod to which the
first ring is attached. If the first first is removed, then
the third ring is no longer blocked by the first ring's iron
rod and can be removed freely. The second ring, however
cannot be moved if the first ring is gone because it will
then be blocked by the first ring in its new position
outside of the U.
outside of the `U`.
Here is an illustration of the three-ring case. The bottom
of the puzzle is on the left-hand side of the page.
```
@@ -105,7 +106,8 @@ of the puzzle is on the left-hand side of the page.
\ | \\ ||
\ | \\||
\| \||
```
This puzzle takes other forms as well. One such puzzle is
called "Spin-Out". This puzzle consists of one plastic
piece that encases another piece that can slide in and out
@@ -131,14 +133,14 @@ free to move. The only other piece that is free to move is
the second one that is still attached to the base it is
trying to be freed from. In the case of the original
puzzle, consider the rings numbered from 1 to 6 with ring 1
being the one at the closed send of the U. Ring 1 can
always be removed from or added to the U. In the initial
state, when all rings are around the U, ring 2 is the other
being the one at the closed end of the `U`. Ring 1 can
always be removed from or added to the `U`. In the initial
state, when all rings are around the `U`, ring 2 is the other
one that can be moved because it is second. If ring 1 is
removed, then only two operations are possible: the
restoration of ring 1 and the removal of ring 3. This is
because ring 1 is always movable, and ring 3 is currently
the second ring still attached to the U. This constraint
the second ring still attached to the `U`. This constraint
leads to a recursive solution to the puzzle. Like the
[Towers of Hanoi](hanoi.md), the number of steps to solve this puzzle is
exponential in the number of rings.