Homework Assignment 5-Appendix A
Tomohiro Oda
board := JunMatrix new: 10.
1 to: 10 do: [ :x | board atPoint: x@1 put: 0. board atPoint: x@10 put: -1].
1 to: 10 do: [ :y | board atPoint: 1@y put: 0. board atPoint: 10@y put: -1].
board atPoint: 2@2 put: -1.
board atPoint: 9@9 put: -1.
at := [ :p | board atPoint: p+(1@1)].
place := [:p :value | board atPoint: p+(1@1) put: value ].
remove := [:p | board atPoint: p+(1@1) put: nil ].
isClear := [ :p | (at value: p) isNil].
isClearH := [ :p | (isClear value: p) and: [isClear value: p +(1@0)]].
isClearV := [ :p | (isClear value: p) and: [isClear value: p +(0@1)]].
piecesLeft := 31.
placeH :=
[ :p |
(isClearH value: p)
and:
[place value: p value: piecesLeft.
place value: p + (1@0) value: piecesLeft.
piecesLeft := piecesLeft - 1.
true]].
placeV :=
[ :p |
(isClearV value: p)
and:
[place value: p value: piecesLeft.
place value: p+(0@1) value: piecesLeft.
piecesLeft := piecesLeft - 1.
true]].
unplaceH :=
[ :p |
place value: p value: nil.
place value: p+(1@0) value: nil.
piecesLeft := piecesLeft + 1].
unplaceV :=
[ :p |
place value: p value: nil.
place value: p+(0@1) value: nil.
piecesLeft := piecesLeft + 1].
isLeftTopCorner :=
[ :p |
(isClear value: p-(1@1)) not and: [(isClear value: p-(1@0)) not and: [(isClear value: p-(0@1)) not and: [isClear value: p]]]].
findPlace :=
[ | x y |
x := (1 to: 8) detect: [ :t | y := (1 to: 8) detect: [ :u | isLeftTopCorner value: t@u ] ifNone: [nil]. y notNil] ifNone: [nil].
x notNil ifTrue: [x@y] ifFalse: [nil]].
step := nil.
tryH := [ :p | (placeH value: p) and: [step value or: [unplaceH value: p. false]]].
tryV := [ :p | (placeV value: p) and: [step value or: [unplaceV value: p. false]]].
step :=
[piecesLeft = 0
ifTrue: [true]
ifFalse:
[| p |
p := findPlace value.
p isNil
ifTrue: [self halt. false]
ifFalse:
[(tryH value: p) or: [tryV value: p]]]].
step value ifTrue: [board] ifFalse: [false]
          
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