ref: 944997d2f936150d8efbaba6dcb3e237b5658761
parent: b35bedd60c87e362f2dd59760aa8bf340fa3b428
author: Simon Tatham <anakin@pobox.com>
date: Sat May 7 08:30:29 EDT 2005
Aha, here's a nice easy way to generate really hard puzzles. Added the missing fifth difficulty level to Solo: `Unreasonable', in which even set-based reasoning is insufficient and there's no alternative but to guess a number and backtrack if it didn't work. (Solutions are still guaranteed unique, however.) In fact it now seems to take less time to generate a puzzle of this grade than `Advanced'! [originally from svn r5756]