ref: 93103eeca4e41ecaa874069b10f2a3de8c392435
parent: d2369aab621c80449db7c589f0c65c722802b8b4
author: Simon Tatham <anakin@pobox.com>
date: Mon Apr 7 11:56:42 EDT 2008
Substantial reworking of Solo so that it implements both Sudoku-X (require both main diagonals to have one of every digit in addition to all the usual constraints) and Jigsaw Sudoku (replace the array of rectangular sub-blocks with the sub-blocks being random polyominoes). To implement the latter, I've moved my `divvy.c' library routine out of the `unfinished' subdirectory. Jigsaw mode is currently an undocumented feature: you enable it by setting the rows parameter to 1 (and the columns parameter to your desired grid size, which unlike normal Sudoku can be anything you like including a prime number). The reason it's undocumented is because generation times are not yet reliably short: sometimes generating a jigsaw-type puzzle can hang for hours and still get nowhere. (The algorithm should terminate in principle, but not in any time you're prepared to wait.) I _think_ I know how to solve this, but have yet to try it. Until then, jigsaw mode will remain a hidden feature. Printing of X-type puzzles is also substandard at present, because the current print-colour API replaces the desired light shading of the X-cells with heavy diagonal hatching. I plan to adjust the API imminently to address this. [originally from svn r7974]