3 ms·

Oops, must have missed it. Thanks for the clarification.

• dingo_bat 9y ago
  It says they used a "traditional recursive algorithm", probably referring to the backtracking solution. In my experience it's fast enough to not matter for this sort of application (the other things that are going on are 1000x more complex).
  • eutectic 9y ago
    There is a small fraction puzzles for which simple backtracking gets stuck on unproductive branches and essentially never finishes.
    • yeldarb 9y ago
      Do you have any examples? I'd love to improve the algorithm. Someone on /r/programming pointed me here: http://apollon.issp.u-tokyo.ac.jp/~watanabe/sample/sudoku/index.html http://apollon.issp.u-tokyo.ac.jp/~watanabe/sample/sudoku/in... But the app seems to already handle those Ok without doing anything special: https://www.dropbox.com/s/arfd03kr8ieczk5/recursive-solver-killer.mov?dl=0 https://www.dropbox.com/s/arfd03kr8ieczk5/recursive-solver-k...