Class ConstraintUtil

Provides utilities for easily implementing constraints.

Inheritance

System.Object

ConstraintUtil

Inherited Members

System.Object.Equals(System.Object)

System.Object.Equals(System.Object, System.Object)

System.Object.GetHashCode()

System.Object.GetType()

System.Object.MemberwiseClone()

System.Object.ReferenceEquals(System.Object, System.Object)

System.Object.ToString()

Namespace: SudokuSpice.ConstraintBased.Constraints

Assembly: SudokuSpice.dll

Syntax

public static class ConstraintUtil

Methods

TryAddObjectiveForPossibilityIndex(ReadOnlySpan<Possibility[]>, Int32, ExactCoverGraph, Int32, out Objective)

Add an Objective connecting all the Possibilitys at the given possibilityIndex on the given squares. Skips null squares, null possibilities, and any possibilities in a known state (i.e. dropped or selected).

Declaration

public static bool TryAddObjectiveForPossibilityIndex(ReadOnlySpan<Possibility[]> squares, int possibilityIndex, ExactCoverGraph graph, int requiredCount, out Objective objective)

Parameters

Type	Name	Description
System.ReadOnlySpan<Possibility[]>	squares	The squares to add Possibilitys from.
System.Int32	possibilityIndex	The value index of the possible value within the squares.
ExactCoverGraph	graph	The graph for the current puzzle being solved.
System.Int32	requiredCount	The number of possibilities required to satisfy the new Objective.
Objective	objective	The new objective, if successful, else null.

Returns

Type	Description
System.Boolean	False if the objective could not be added, for example because not enough Possibility objects were still possible to satisfy it, else true.

TryAddOptionalObjectiveForPossibilityIndex(ReadOnlySpan<Possibility[]>, Int32, Int32, out OptionalObjective)

Add an OptionalObjective connecting all the Possibilitys at the given possibilityIndex on the given squares. Skips null squares, null possibilities, and any possibilities in a known state (i.e. dropped or selected).

Declaration

public static bool TryAddOptionalObjectiveForPossibilityIndex(ReadOnlySpan<Possibility[]> squares, int possibilityIndex, int requiredCount, out OptionalObjective objective)

Parameters

Type	Name	Description
System.ReadOnlySpan<Possibility[]>	squares	The squares to add Possibilitys from.
System.Int32	possibilityIndex	The value index of the possible value within the squares.
System.Int32	requiredCount	The number of possibilities required to satisfy the new OptionalObjective.
OptionalObjective	objective	The new optional objective, if successful, else null.

Returns

Type	Description
System.Boolean	False if the objective could not be added, for example because not enough Possibility objects were still possible to satisfy it, else true.

TryCheckForSetValues(IReadOnlyPuzzle, ExactCoverGraph, ReadOnlySpan<Coordinate>, Span<Boolean>)

Tries to fill the isValueIndexPresentInSquares span according to which value indices are already set in the given list of squareCoordinates. Each index is true if that value is already set.

Results are only complete if this returns true. If it returns false, no guarantees are made as to the state of isValueIndexPresentInSquares.

Declaration

public static bool TryCheckForSetValues(IReadOnlyPuzzle puzzle, ExactCoverGraph graph, ReadOnlySpan<Coordinate> squareCoordinates, Span<bool> isValueIndexPresentInSquares)

Parameters

Type	Name	Description
IReadOnlyPuzzle	puzzle	The current puzzle being solved.
ExactCoverGraph	graph	The graph for the puzzle being solved.
System.ReadOnlySpan<Coordinate>	squareCoordinates	The coordinates to check.
System.Span<System.Boolean>	isValueIndexPresentInSquares	An array that will be updated to indicate which values are set.

Returns

Type	Description
System.Boolean	False if a value is duplicated in the given coordinates.

TryDropPossibilitiesAtIndex(ReadOnlySpan<Possibility[]>, Int32)

Drops Possibilitys with the given possibilityIndex from the given set of squares. Null squares and possible values are ignored.

If this returns false, there is no guarantee as to the state of the given squares. Some may have been dropped.

Declaration

public static bool TryDropPossibilitiesAtIndex(ReadOnlySpan<Possibility[]> squares, int possibilityIndex)

Parameters

Type	Name	Description
System.ReadOnlySpan<Possibility[]>	squares	The squares to drop, if not null.
System.Int32	possibilityIndex	The index of the possibility within the squares.

Returns

Type	Description
System.Boolean	True if all the squares were dropped safely (eg. without resulting in any Objective that can no longer be satisfied).

TryImplementUniquenessConstraintForSquares(IReadOnlyPuzzle, ReadOnlySpan<Coordinate>, ExactCoverGraph)

Enforces uniqueness of the values at the given coordinates.

Declaration

public static bool TryImplementUniquenessConstraintForSquares(IReadOnlyPuzzle puzzle, ReadOnlySpan<Coordinate> squareCoordinates, ExactCoverGraph graph)

Parameters

Type	Name	Description
IReadOnlyPuzzle	puzzle	The puzzle being solved.
System.ReadOnlySpan<Coordinate>	squareCoordinates	The coordinates that must contain unique values.
ExactCoverGraph	graph	The exact-cover graph for the current puzzle.

Returns

Type	Description
System.Boolean	False if the puzzle violates uniquness for the given coordinates, else true.

Remarks

This drops any Possibilitys that are no longer possible, and adds Objectives to enforce this constraint for the ones that are still possible.