constraint propagation
Posts tagged "constraint propagation"
3 posts
The mathematics of Nikoli puzzles
Cell Blocks, Nurikabe and Slitherlink share no rules, but they share a shape: local arithmetic plus one global topological constraint. That split explains where the difficulty lives, why propagation always stops short, and what a puzzle with a well-behaved global constraint would look like.
Nurikabe, and what replaces candidate enumeration
A puzzle that keeps the clue semantics of Shikaku but destroys the representation its solver depends on, forcing a switch from candidate lists to reachability, liberties and articulation reasoning.
The mathematics of Cell Blocks
A pencil puzzle whose solver is an exact cover problem, whose difficulty dial is the divisor-count function, and whose harder variants each break exactly one assumption the solver leans on.