Solver find solutions method

SudoScript.Core.Test/BoardTests.cs

@@ -0,0 +1,136 @@
+using NUnit.Framework;
+using SudoScript.Core;
+using SudoScript.Core.Data;
+
+namespace SudoScript.Core.Test;
+
+internal sealed class BoardTests
+{
+    [Test]
+    public void ValidateBoardInvalidRuleTest()
+    {
+        Board board = Util.CreateStandardEmpty();
+        board[5, 1].Digit = 2;
+        board[4, 8].Digit = 7;
+        board[5, 2].Digit = 2;
+        board[8, 4].Digit = 4;
+
+        Assert.That(board.Validate(), Is.False);
+    }
+
+    [Test]
+    public void ValidateBoardValidRuleTest()
+    {
+        Board board = Util.CreateStandardEmpty();
+        board[5, 1].Digit = 2;
+        board[4, 8].Digit = 7;
+        board[8, 4].Digit = 4;
+        board[5, 2].Digit = 3;
+
+        Assert.That(board.Validate(), Is.True);
+    }
+
+    [Test]
+    public void ValidateBoardNoCandidatesTest()
+    {
+        Board board = Util.CreateStandardEmpty();
+
+        board[9, 9].EliminateCandidate(1);
+        board[9, 9].EliminateCandidate(2);
+        board[9, 9].EliminateCandidate(3);
+        board[9, 9].EliminateCandidate(4);
+        board[9, 9].EliminateCandidate(5);
+        board[9, 9].EliminateCandidate(6);
+        board[9, 9].EliminateCandidate(7);
+        board[9, 9].EliminateCandidate(8);
+        board[9, 9].EliminateCandidate(9);
+
+        Assert.That(board.Validate(), Is.False);
+    }
+
+    [Test]
+    public void BoardEqualsTest()
+    {
+        Board board = Util.CreateStandardEmpty();
+        board[5, 1].Digit = 2;
+        board[4, 8].Digit = 7;
+        board[5, 2].Digit = 3;
+        board[8, 4].Digit = 4;
+
+        Board board2 = Util.CreateStandardEmpty();
+        board2[5, 1].Digit = 2;
+        board2[4, 8].Digit = 7;
+        board2[5, 2].Digit = 3;
+        board2[8, 4].Digit = 4;
+
+        Assert.That(board2, Is.EqualTo(board));
+    }
+
+    [Test]
+    public void BoardNotEqualsTest()
+    {
+        Board board = Util.CreateStandardEmpty();
+        board[1, 1].Digit = 2;
+        board[4, 8].Digit = 7;
+        board[5, 3].Digit = 3;
+        board[8, 4].Digit = 4;
+
+        Board board2 = Util.CreateStandardEmpty();
+        board2[1, 1].Digit = 1;
+        board2[4, 8].Digit = 7;
+        board2[5, 3].Digit = 3;
+        board2[8, 4].Digit = 4;
+
+        Assert.That(board2, Is.Not.EqualTo(board));
+    }
+
+    [Test]
+    public void BoardHashTest()
+    {
+        Board board = Util.CreateStandardEmpty();
+        board[5, 1].Digit = 2;
+        board[4, 8].Digit = 7;
+        board[5, 2].Digit = 3;
+        board[8, 4].Digit = 4;
+
+        Board board2 = Util.CreateStandardEmpty();
+        board2[5, 1].Digit = 2;
+        board2[4, 8].Digit = 7;
+        board2[5, 2].Digit = 3;
+        board2[8, 4].Digit = 4;
+
+        Assert.That(board2.GetHashCode(), Is.EqualTo(board.GetHashCode()));
+    }
+
+    [Test]
+    public void BoardHashNotEqualTest()
+    {
+        Board board = Util.CreateStandardEmpty();
+        board[5, 1].Digit = 2;
+        board[4, 8].Digit = 7;
+        board[5, 2].Digit = 3;
+        board[8, 4].Digit = 4;
+
+        Board board2 = Util.CreateStandardEmpty();
+        board2[5, 1].Digit = 2;
+        board2[4, 9].Digit = 7;
+        board2[5, 2].Digit = 3;
+        board2[8, 4].Digit = 4;
+
+        Assert.That(board2.GetHashCode(), Is.Not.EqualTo(board.GetHashCode()));
+    }
+
+    [Test]
+    public void CloneTest()
+    {
+        Board board = Util.CreateStandardEmpty();
+        board[5, 1].Digit = 2;
+        board[4, 8].Digit = 7;
+        board[5, 2].Digit = 3;
+        board[8, 4].Digit = 4;
+
+        Board clonedBoard = board.Clone();
+
+        Assert.That(board, Is.EqualTo(clonedBoard));
+    }
+}

SudoScript.Core.Test/SolverTests.cs

@@ -1,22 +1,14 @@
 using NUnit.Framework;
+using StandardLibrary;
 using SudoScript.Core;
 using SudoScript.Core.Data;
+using System.Data;
 
 namespace SudoScript.Core.Test;
 
 internal sealed class SolverTests
 {
-    [Test()]
-    public void CanSolveEmptySudoku()
-    {
-        Board board = Util.CreateStandardEmpty();
-        Assert.DoesNotThrow(() => board = Solver.Solve(board));
-        Assert.IsTrue(board.ValidateRules());
-        Assert.IsFalse(board.Cells().Any(c => c.Digit == Cell.EmptyDigit));
-    }
-
-    [Test]
-    public void CanSolveGeneratedSudoku()
+    public Board CreateEasyBoard()
     {
         Board board = Util.CreateStandardEmpty();
         // Sudoku givens generated by https://sudoku.com/
@@ -39,6 +31,7 @@ public void CanSolveGeneratedSudoku()
         board[8, 4].Digit = 8;
 
         board[3, 5].Digit = 4;
+        board[4, 7].Digit = 2;
 
         board[3, 6].Digit = 6;
         board[5, 6].Digit = 7;
@@ -50,6 +43,7 @@ public void CanSolveGeneratedSudoku()
         board[8, 7].Digit = 3;
         board[9, 7].Digit = 5;
 
+        board[3, 9].Digit = 1;
         board[2, 8].Digit = 9;
         board[4, 8].Digit = 7;
         board[5, 8].Digit = 4;
@@ -59,6 +53,23 @@ public void CanSolveGeneratedSudoku()
         board[7, 9].Digit = 9;
         board[8, 9].Digit = 7;
 
+        return board;
+    }
+
+    [Test()]
+    public void CanSolveEmptySudoku()
+    {
+        Board board = Util.CreateStandardEmpty();
+        Assert.DoesNotThrow(() => board = Solver.Solve(board));
+        Assert.IsTrue(board.ValidateRules());
+        Assert.IsFalse(board.Cells().Any(c => c.Digit == Cell.EmptyDigit));
+    }
+
+    [Test]
+    public void CanSolveGeneratedSudoku()
+    {
+        Board board = CreateEasyBoard();
+
         Console.WriteLine(board.ToString());
 
         Console.WriteLine("-------------------------------------------------");
@@ -68,4 +79,56 @@ public void CanSolveGeneratedSudoku()
 
         Console.WriteLine(board.ToString());
     }
+
+    [Test]
+    public void IsSatisfactoryTest()
+    {
+        Board board = CreateEasyBoard();
+
+        Assert.IsTrue(Solver.IsSatisfactory(board));
+    }
+
+    [Test]
+    public void IsNotSatisfactoryTest()
+    {
+        Board board = Util.CreateStandardEmpty();
+
+        Assert.IsFalse(Solver.IsSatisfactory(board));
+    }
+
+    [Test]
+    public void FindSolutionsTwoUniqueCellsTest()
+    {
+
+        Board board = new(new List<Cell>{ new Cell(1, 1), new Cell(1, 2) }, 
+            new List<Unit> {
+                new Unit(new List<CellReference> { 
+                    new CellReference(1, 1), 
+                    new CellReference(1,2) }, 
+                new List<IRule> { new Unique { } })});
+
+        List<Board>? boardList = Solver.FindSolutions(board);
+        List<Board>? randomBoardList = Solver.FindSolutions(board, int.MaxValue, true);
+
+        Assert.IsNotNull(boardList);
+        Assert.That(boardList.Count(), Is.EqualTo(72));
+        Assert.IsNotNull(randomBoardList);
+        Assert.That(boardList.Count(), Is.EqualTo(randomBoardList.Count()));
+    }
+
+    [Test]
+    public void FindNumberOfSolutionsTest()
+    {
+        Board board = new(new List<Cell> { new Cell(1, 1), new Cell(1, 2) },
+            new List<Unit> {
+                new Unit(new List<CellReference> {
+                    new CellReference(1, 1),
+                    new CellReference(1,2) },
+                new List<IRule> { new Unique { } })});
+
+        List<Board>? boardList = Solver.FindSolutions(board, 25);
+
+        Assert.IsNotNull(boardList);
+        Assert.That(boardList.Count(), Is.EqualTo(25));
+    }
 }

SudoScript.Core/Data/Board.cs

@@ -88,6 +88,22 @@ public bool ValidateRules()
         return true;
     }
 
+    public bool Validate()
+    {
+        if ((_cells == null) || !this.ValidateRules())
+        {
+            return false;
+        }
+        foreach (Cell cell in this.Cells())
+        {
+            if (cell.CandidateCount < 1)
+            {
+                return false;
+            }
+        }
+        return true;
+    }
+
     public bool IsSolved()
     {
         return ValidateRules() && Cells().All(c => c.Digit != Cell.EmptyDigit);
@@ -120,4 +136,45 @@ public override string ToString()
 
         return s.ToString();
     }
+
+    public override bool Equals(object? obj)
+    {
+        if (obj == null || GetType() != obj.GetType())
+        {
+            return false;
+        }
+
+        Board other = (Board)obj;
+
+        if (other.Cells().Count() != _cells.Count)
+        {
+            return false;
+        }
+
+        foreach (Cell cell1 in _cells.Values)
+        {
+            if (!other.TryGetCell(cell1.X, cell1.Y, out Cell? cell2))
+            {
+                // Compared board does not contain cell with these coordinates
+                return false;
+            }
+            // Compare cells
+            if (!cell1.Equals(cell2))
+            {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    public override int GetHashCode()
+    {
+        int hash = 17;
+        foreach (var cell in _cells.Values)
+        {
+            hash = hash * 31 + cell.GetHashCode();
+        }
+        return hash;
+    }
 }

SudoScript.Core/Data/Cell.cs

@@ -142,4 +142,46 @@ public string ToString(string format)
             .Replace("Y", Y.ToString());
     }
 
+    public override bool Equals(object? obj)
+    {
+        if (obj == null || GetType() != obj.GetType())
+        {
+            return false;
+        }
+
+        Cell other = (Cell)obj;
+
+        // Check coordinates and digit
+        if (!((this.Y == other.Y) && (this.X == other.X) && (this.Digit == other.Digit)))
+        {
+            return false;
+        }
+
+        // Check candidates
+        for (int i = 1; i <= 9; i++)
+        {
+            if (this.HasCandidate(i) != other.HasCandidate(i))
+            {
+                return false;
+            }
+            if (this.IsGiven != other.IsGiven)
+            {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    public override int GetHashCode()
+    {
+        unchecked
+        {
+            int hash = 17;
+            hash = hash * 23 + X.GetHashCode();
+            hash = hash * 23 + Y.GetHashCode();
+            hash = hash * 23 + Digit.GetHashCode();
+            return hash;
+        }
+    }
+
 }