solutions ( puzzle random? -- solutions )

Vocabulary

sudokus

Inputs

puzzle	an object
random?	an object

Outputs

solutions

an object

Definition

USING: arrays kernel lists monads ranges sequences sets ;

IN: sudokus

:: solutions ( puzzle random? -- solutions )
    f puzzle random?
    [ indices [ f ] [ random? swap nth-or-lower ] if-empty ]
    [ index ] if [| pos |
        1 9 [a..b] 80 <iota> [ pos near ] filter
        [ puzzle nth ] map members diff
        [ 1array puzzle pos cut-slice rest surround ] map >list
        [ random? solutions ] bind
    ] [ puzzle list-monad return ] if* ;