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Zebra puzzle: Difference between revisions
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→General solver with relational algebra: update to stricter typing
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m (→General solver with relational algebra: update to stricter typing) |
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A general solver for this type of puzzle, using relational algebra. This solver can also be used for "Dinesman's multiple-dwelling problem"
<lang tailspin>
// There are five houses.
// The English man lives in the red house.
// The Swede has a dog.
// The Dane drinks tea.
// The green house is immediately to the left of the white house.
// They drink coffee in the green house.
// The man who smokes Pall Mall has birds.
// In the yellow house they smoke Dunhill.
// In the middle house they drink milk.
// The Norwegian lives in the first house.
// The man who smokes Blend lives in the house next to the house with cats.
// In a house next to the house where they have a horse, they smoke Dunhill.
// The man who smokes Blue Master drinks beer.
// The German smokes Prince.
// The Norwegian lives next to the blue house.
// They drink water in a house next to the house where they smoke Blend.
//
// The question is, who owns the zebra?
//
//Additionally, list the solution for all the houses.
//Optionally, show the solution is unique.
processor EinsteinSolver
@: [{|{}|}]; // A list of possible relations, start with one relation with an empty tuple
Line 7,014 ⟶ 7,038:
operator (a nextTo&{byField:, bMinusA:} b)
▲ data ES_temp__ <"1"> local
@EinsteinSolver: [$@EinsteinSolver... -> \(
def in: $;
def temp: {| $... -> {$, ES_temp__: ($(byField)::raw)"1"} |};
def numbers: [$temp({ES_temp__:})... -> $.ES_temp__];
$numbers... -> \(
def aNumber: $;
def bNumbers: [$bMinusA... -> ($ + $aNumber)"1"];
def new: ($temp matching {| {$a, ES_temp__: $aNumber} |});
@: ($new union (($temp notMatching {| $a |}) notMatching {| {ES_temp__: $aNumber} |}));
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