public void Constrain_ReturnsExpectedConstraints()
{
int size = 4;
int[] possibleValues = new int[] { 1, 3, 5, 7 };
var puzzle = new Puzzle(size);
var matrix = new ExactCoverMatrix(puzzle);
new RowUniquenessConstraint().Constrain(puzzle, matrix);
Assert.Equal(size * possibleValues.Length, matrix.GetUnsatisfiedConstraintHeaders().Count());
ConstraintHeader firstRowConstraint = matrix.GetSquare(new Coordinate(0, 0)).AllPossibleValues[0].FirstLink.Constraint;
ConstraintHeader secondRowConstraint = matrix.GetSquare(new Coordinate(1, 0)).AllPossibleValues[0].FirstLink.Constraint;
ConstraintHeader thirdRowConstraint = matrix.GetSquare(new Coordinate(2, 0)).AllPossibleValues[0].FirstLink.Constraint;
ConstraintHeader fourthRowConstraint = matrix.GetSquare(new Coordinate(3, 0)).AllPossibleValues[0].FirstLink.Constraint;
Assert.NotSame(firstRowConstraint, secondRowConstraint);
Assert.NotSame(firstRowConstraint, thirdRowConstraint);
Assert.NotSame(firstRowConstraint, fourthRowConstraint);
Assert.NotSame(secondRowConstraint, thirdRowConstraint);
Assert.NotSame(secondRowConstraint, fourthRowConstraint);
Assert.NotSame(thirdRowConstraint, fourthRowConstraint);
Assert.Same(firstRowConstraint, matrix.GetSquare(new Coordinate(0, 1)).AllPossibleValues[0].FirstLink.Constraint);
Assert.Same(firstRowConstraint, matrix.GetSquare(new Coordinate(0, 2)).AllPossibleValues[0].FirstLink.Constraint);
Assert.Same(firstRowConstraint, matrix.GetSquare(new Coordinate(0, 3)).AllPossibleValues[0].FirstLink.Constraint);
Assert.Same(secondRowConstraint, matrix.GetSquare(new Coordinate(1, 1)).AllPossibleValues[0].FirstLink.Constraint);
Assert.Same(secondRowConstraint, matrix.GetSquare(new Coordinate(1, 2)).AllPossibleValues[0].FirstLink.Constraint);
Assert.Same(secondRowConstraint, matrix.GetSquare(new Coordinate(1, 3)).AllPossibleValues[0].FirstLink.Constraint);
Assert.Same(thirdRowConstraint, matrix.GetSquare(new Coordinate(2, 1)).AllPossibleValues[0].FirstLink.Constraint);
Assert.Same(thirdRowConstraint, matrix.GetSquare(new Coordinate(2, 2)).AllPossibleValues[0].FirstLink.Constraint);
Assert.Same(thirdRowConstraint, matrix.GetSquare(new Coordinate(2, 3)).AllPossibleValues[0].FirstLink.Constraint);
Assert.Same(fourthRowConstraint, matrix.GetSquare(new Coordinate(3, 1)).AllPossibleValues[0].FirstLink.Constraint);
Assert.Same(fourthRowConstraint, matrix.GetSquare(new Coordinate(3, 2)).AllPossibleValues[0].FirstLink.Constraint);
Assert.Same(fourthRowConstraint, matrix.GetSquare(new Coordinate(3, 3)).AllPossibleValues[0].FirstLink.Constraint);
}
public void TrySelect_SatisfiesConstraints()
{
var puzzle = new Puzzle(4);
var matrix = new ExactCoverMatrix(puzzle);
new RowUniquenessConstraint().Constrain(puzzle, matrix);
new ColumnUniquenessConstraint().Constrain(puzzle, matrix);
int valueIndex = 0;
PossibleValue possibleValue = matrix.GetSquare(new Coordinate(0, 1)).GetPossibleValue(valueIndex);
Assert.True(possibleValue.TrySelect());
ConstraintHeader constraintA = possibleValue.FirstLink.Constraint;
ConstraintHeader constraintB = possibleValue.FirstLink.Right.Constraint;
Assert.True(constraintA.IsSatisfied);
Assert.True(constraintB.IsSatisfied);
Assert.Equal(4, constraintA.Count);
Assert.Equal(4, constraintB.Count);
Assert.DoesNotContain(constraintA, matrix.GetUnsatisfiedConstraintHeaders());
Assert.DoesNotContain(constraintB, matrix.GetUnsatisfiedConstraintHeaders());
}
