Comment ioccc 2013 US president matching code (Score 4, Interesting) 172
The International Obfuscated C Code contest had a winning entry that could flag the names of US presidents as republican or democrat.
main(int riguing,char**acters){puts(1[acters-~!(*(int*)1[acters]%4796%275%riguing)]);}
Quoting: "This one-line C program accepts as a first command-line argument the last name of any of the last 31 US Presidents (from Franklin Pierce onwards), in lower case, and prints out their political affiliation. Use "republican" as the 2nd command-line argument, and "democrat" as the 3rd (or equivalent strings of your choice)."
De-obfuscated, it is a boolean expression acting on a string s,
(*(int*)s)%4796%275%4
I wonder whether you can make a regexp that is shorter than this and accomplishes the same thing.