Implementation of the extremely fast algorithm X, using dancing links as main data structure, solving sudokus. Solves all of the top 95 hardest sudokus in approximately 0.05 seconds.
https://arxiv.org/pdf/cs/0011047v1.pdf
./DLX input-filename
A puzzle must be in a single row, empty cells are represented as dots:
3...8.......7....51..............36...2..4....7...........6.13..452...........8..
The executable solves all the puzzles in the input file.