% time ./challenge < words.txt > digest.txt
Reading in single words.
61406 single words.
Finding all useful single words.
3477 useful single words.
Listing all pairs of words.
6043026 total pairs.
Finding all useful pairs.
14574 useful pairs.
Listing all triples of words.
50644650 total triples.
Finding all useful triples.
289 useful triples.
Finding a single universal quadruple.
Universal quadruple found.
952.27u 3.88s 15:57.57 99.8%