Glenn Fowler of AT&T Labs
wrote an excellent Sudoku application - Sudocoup
- which I have envied for some time. As I developed my own Sudoku solver, I compared its execution time for various puzzles to that of Sudocoup.
In April, Sudocoup could solve 9x9 puzzles that mine could not. By June, my solver could do any puzzle up to 36x36 - but far slower than Sudocoup. In July, I implemented a raft of additional constraint logic reduction routines that allowed solving 64x64 puzzles in a few minutes - as compared to the seconds required by Sudocoup. 144x144 remained completely out of reach.
However, I finished implementing single-node chain reduction for my solver, which I named Arcterik Sudoku. Arcterik Sudoku solves this 256x256
puzzle in 0.635
seconds, whereas Sudocoup requires 3 minutes, 26 seconds
So, I've hit the faster than Sudocoup
milestone that seemed unreachable for so long. My ultimate goal for this project, aside from sharpening my graph theory and learning some new things, is to handle 65536x65536 puzzles in reasonable time.
16x16 in the titlebar refers to block size - 16*16=256, the width of the puzzle