Sudoku: Difference between revisions

Line 4,177:

/// Dictionary of all peer squares in the relevant units wrt square in question

let peers =

[for s in squares do units.[s] |> Array.concat |> Array.distinct |> Array.except [s] |> tuple2 s]

[for s in squares do units[s] |> Array.concat |> Array.distinct |> Array.except [s] |> tuple2 s]

|> Map.ofList

/// Eliminate d from values[s] and propagate when values = 1.

/// Return Some values, except return None if a contradiction is detected.

let rec eliminate (values:Map<~~string~~,~~int[]~~>) (s:string) d =

let rec eliminate (values:Map<_,_>) (s:string) d =

let peerElim (vx:Map<~~string~~,~~int[]~~>) =

let peerElim (vx:Map<_,_>) =

match Seq.length vx[s] with // (1) If a square s is reduced to one value d, then eliminate d from the peers.

| 0 -> None // removed last value

Line 4,191:

let unitsElim vx =

units[s] // (2) If a unit u is reduced to only one place for a value d, then put it there.

|> List.ofArray |> all (fun (st:Map<~~string~~,~~int[]~~>) u ->

|> List.ofArray |> all (fun (st:Map<_,_>) u ->

let dKeys = [for s in u do if st[s] |> Seq.contains d then s]

match Seq.length dKeys with

Line 4,220:

/// Convert grid to a Map of constraint popagated possible values, or return None if a contradiction is detected.

let applyCPS (parsedGrid:Map<~~string~~,~~int~~>) =

let applyCPS (parsedGrid:Map<_,_>) =

let values = [for s in squares do s, digits]|> Map.ofList

parsedGrid