From 54eba4aa354b572eafa1daef87e31c3c56623f30 Mon Sep 17 00:00:00 2001
From: Niklas Birk <nikla.birk.nb@gmail.com>
Date: Mon, 12 Apr 2021 16:12:01 +0200
Subject: [PATCH] add new problem "Labyrinthine puzzle" from game Labyrinthine
 Chapter I

---
 src/search/LabyrinthineNode.java | 124 +++++++++++++++++++++++++++++++
 1 file changed, 124 insertions(+)
 create mode 100644 src/search/LabyrinthineNode.java

diff --git a/src/search/LabyrinthineNode.java b/src/search/LabyrinthineNode.java
new file mode 100644
index 0000000..a560e22
--- /dev/null
+++ b/src/search/LabyrinthineNode.java
@@ -0,0 +1,124 @@
+package search;
+
+import java.util.*;
+
+public class LabyrinthineNode extends Node<boolean[][]>
+{
+    public LabyrinthineNode(final boolean[][] state)
+    {
+        super(state);
+    }
+
+    private LabyrinthineNode(final boolean[][] value, final Node<boolean[][]> parent, final int heuristicCosts)
+    {
+        super(value, parent, heuristicCosts);
+    }
+
+    @Override
+    public boolean isTargetReached(final Node<boolean[][]> target)
+    {
+        return valueEquals(target);
+    }
+
+    @Override
+    public List<Node<boolean[][]>> generateSuccessors()
+    {
+        final var successors = new ArrayList<Node<boolean[][]>>();
+        final var offPositions = detectOffPositions();
+
+        for (final var pos : offPositions)
+        {
+            final var newState = copyOfState();
+
+            toggleStateAtPos(newState, new IntPair(pos.x(), pos.y()));
+            toggleStateAtPos(newState, new IntPair(pos.x(), pos.y() + 1));
+            toggleStateAtPos(newState, new IntPair(pos.x(), pos.y() - 1));
+            toggleStateAtPos(newState, new IntPair(pos.x() + 1, pos.y()));
+            toggleStateAtPos(newState, new IntPair(pos.x() - 1, pos.y()));
+
+            final var successor = new LabyrinthineNode(newState, this, super.heuristicCosts + 1);
+
+            if (!successor.valueEquals(this) && !successor.valueEquals(super.getParent()))
+            {
+                successors.add(successor);
+            }
+        }
+
+        return successors;
+    }
+
+    @Override
+    public String toString()
+    {
+        final var builder = new StringBuilder();
+
+        for (final var row : super.value)
+        {
+            builder.append(Arrays.toString(row)).append("\n");
+        }
+
+        return builder.toString();
+    }
+
+    private boolean valueEquals(final Node<boolean[][]> node)
+    {
+        if (node == null)
+        {
+            return false;
+        }
+
+        for (var row = 0; row < super.value.length; row++)
+        {
+            for (var col = 0; col < super.value[row].length; col++)
+            {
+                if (super.value[row][col] != node.value[row][col])
+                {
+                    return false;
+                }
+            }
+        }
+
+        return true;
+    }
+
+    private List<IntPair> detectOffPositions()
+    {
+        final var positions = new ArrayList<IntPair>();
+
+        for (var row = 0; row < super.value.length; row++)
+        {
+            for (var col = 0; col < super.value[row].length; col++)
+            {
+                if (!super.value[row][col])
+                {
+                    positions.add(new IntPair(col, row));
+                }
+            }
+        }
+
+        return positions;
+    }
+
+    private boolean[][] copyOfState()
+    {
+        final var copy = new boolean[super.value.length][super.value[0].length];
+
+        for (var y = 0; y < copy.length; y++)
+        {
+            System.arraycopy(super.value[y], 0, copy[y], 0, copy.length);
+        }
+
+        return copy;
+    }
+
+    private void toggleStateAtPos(boolean[][] newState, IntPair pos)
+    {
+        try
+        {
+            newState[pos.y()][pos.x()] = !newState[pos.y()][pos.x()];
+        }
+        catch (final ArrayIndexOutOfBoundsException ignored)
+        {
+        }
+    }
+}
\ No newline at end of file