Add try.sh and hint.md to 2012/hou + formatting

The hint.md file is necessary as the '#' header in it specifies the
title and stylesheet as part of the entry.

The try.sh script is as usual.

Format/typo check README.md file. The hint.md file formatting was not
changed due to the regexp engine amongst other reasons. Just obvious
spelling errors were updated.

2012/hou/hint.md

@@ -0,0 +1,134 @@
+# Most useful obfuscation
+
+Qiming Hou  
+<hqm03ster@gmail.com>  
+<http://www.houqiming.net>  
+
+
+## Judges' comments:
+
+### To build:
+
+    make hou
+
+### To run:
+
+    ./hou syntax-file file-to-process
+
+### Try (Unix):
+
+The results are best viewed in a 80x25 console with ANSI colors.
+
+    less hou.c
+
+    ./hou ansi.txt hou.c | less -r
+
+    ./hou chk.txt hou.c | wc
+
+    ./hou markdown.txt remarks.markdown > remarks.htm
+    your-browser remarks.htm
+
+### Try (Windows):
+
+    copy header.htm hou.htm /y
+    hou html.txt hou.c >> hou.htm
+    start hou.htm
+
+### Selected Judges Remarks:
+
+What a versatile entry! It can be used to check the size of IOCCC entries *and* to publish them as HTML.
+
+For extra credit: what is the meaning of the number 2321237?
+
+
+## Author's comments:
+
+### Disclaimer
+
+The reviewer may have already noticed that the 2nd page of this program is a
+dense blob, which is discouraged by the contest rules. We wish to point out that
+a majority of state-of-art programming editors support syntax highlighting,
+which should be enabled when reading this entry. Anticipating that the
+reviewer's preferred color setting may produce a suboptimal visual effect, a few
+syntax files are provided to highlight the source code under an author-provided
+setting, using the submitted program itself. Syntax highlighting would also
+visually improve the 3rd page.
+
+The code may throw a few warnings due to formatting constraints. The author did
+try to remove warnings under gcc and Visual Studio, though.
+
+The author does not own the original anime series where the embedded ASCII arts
+come from. For comparison, original non-ASCII art depictions of the relevant
+characters and objects can be found by googling the embedded text messages.
+
+
+### Syntax files
+
+The syntax file consists of a number of rewriting rules. Each rule consists of a
+regular expression, a space, a format string, and a newline. All text matching
+the regular expression would be replaced by the format string. In case of a
+conflict, rules appearing earlier would take precedence. One can refer to the
+original text in the format string using "%s". Other "%" characters in the
+format string must be escaped with another "%". The space character can be used
+in the regular expression by escaping it with [] or "".
+
+The following regular expression operators are supported:
+
+    () [] * + ? | ""
+
+For example, one can use the following expression to match a certain declaration statement in hou.c:
+
+    "char"[ *]*[a-zA-Z_][0-9a-zA-Z_]*[ ]*((=[0-9a-zA-Z_ ]+)|(\[[0-9a-zA-Z_ ]*\]))?[ ]*(,[ *]*[a-zA-Z_][0-9a-zA-Z_]*[ ]*((=[0-9a-zA-Z_ ]+)|(\[[0-9a-zA-Z_ ]*\]))?[ ]*)*;
+
+The regex engine is also algorithmically efficient. To illustrate the point,
+ansi.txt contains a pathological expression [2] that guarantees a hang for the
+competing Perl engine while matching itself. Try to compare these two engines:
+
+    ./hou ansi.txt ansi.txt
+    perl patho.pl < ansi.txt
+
+Finally, there are a few limitations...
+
+
+- The only escape sequence supported is \n and it doesn't work in [].
+- The maximum file/rule size is a linear function of the hard-coded constant M.
+- Single-character matches at the end of file may be missed.
+- The operator | doesn't obey precedence rules and some extra ()s may be required.
+- Incorrect syntax files are not tolerated.
+- The program relies on ASCII.
+
+### Why obfuscated
+
+The first layer of obfuscation comes from the challenge of embedding a large
+ASCII art in a dense blob. The entire art is composed using only keywords,
+strings and character constants. That results in a number of otherwise useless
+defines and quite a number of unconventionally written constants. While the
+preprocessor may remove the former, the later would remain regardless of
+beautification and preprocessing.
+
+The second layer of obfuscation comes from the need to squeeze a reasonably
+powerful regex engine into the remaining area that isn't occupied by excessive
+keywords and useless constants. To achieve this, the regex compiler is written
+using the same threaded virtual machine [1] that parses the regex. Due to
+compiler limitations, the generated VM code also ends up obscured by a large
+amount of spaghetti branches and virtual thread creations. Finally, the VM in
+[1] is extended to track multiple expression matches for the actual formatting.
+
+As an extra tweak, the text message actually does something useful. Remove the
+"Make a contract with me" catch line and the program would cease to function.
+
+
+### References
+
+[1] [Russ Cox, Regular Expression Matching: the Virtual Machine Approach](http://swtch.com/~rsc/regexp/regexp2.html)
+
+[2] [Regular Expression Matching Can Be Simple And Fast (but is slow in Java, Perl, PHP, Python, Ruby, ...)](http://swtch.com/~rsc/regexp/regexp1.html)
+
+--------------------------------------------------------------------------------
+<!--
+(c) Copyright 1984-2015, [Leo Broukhis, Simon Cooper, Landon Curt Noll][judges] - All rights reserved
+This work is licensed under a [Creative Commons Attribution-ShareAlike 3.0 Unported License][cc].
+
+[judges]: http://www.ioccc.org/judges.html
+[cc]: http://creativecommons.org/licenses/by-sa/3.0/
+-->