Simple

src/main/java/model/FirefighterBoard.java

+package model;
+
+import util.Position;
+
+import java.util.*;
+
+
+public class FirefighterBoard implements Board<List<ModelElement>> {
+  private final int columnCount;
+  private final int rowCount;
+  private final int initialFireCount;
+  private final int initialFirefighterCount;
+  private final TargetStrategy targetStrategy = new TargetStrategy();
+  private List<Position> firefighterPositions;
+  private Set<Position> firePositions;
+  private Map<Position, List<Position>> neighbors = new HashMap();
+  private final Position[][] positions;
+  private int step = 0;
+  private final Random randomGenerator = new Random();
+
+  public FirefighterBoard(int columnCount, int rowCount, int initialFireCount, int initialFirefighterCount) {
+    this.columnCount = columnCount;
+    this.rowCount = rowCount;
+    this.positions = new Position[rowCount][columnCount];
+    for (int column = 0; column < columnCount; column++)
+      for (int row = 0; row < rowCount; row++)
+        positions[row][column] = new Position(row, column);
+    for (int column = 0; column < columnCount; column++)
+      for (int row = 0; row < rowCount; row++) {
+        List<Position> list = new ArrayList<>();
+        if (row > 0) list.add(positions[row - 1][column]);
+        if (column > 0) list.add(positions[row][column - 1]);
+        if (row < rowCount - 1) list.add(positions[row + 1][column]);
+        if (column < columnCount - 1) list.add(positions[row][column + 1]);
+        neighbors.put(positions[row][column], list);
+      }
+    this.initialFireCount = initialFireCount;
+    this.initialFirefighterCount = initialFirefighterCount;
+    initializeElements();
+  }
+
+  public void initializeElements() {
+    firefighterPositions = new ArrayList<>();
+    firePositions = new HashSet<>();
+    for (int index = 0; index < initialFireCount; index++)
+      firePositions.add(randomPosition());
+    for (int index = 0; index < initialFirefighterCount; index++)
+      firefighterPositions.add(randomPosition());
+  }
+
+  private Position randomPosition() {
+    return new Position(randomGenerator.nextInt(rowCount), randomGenerator.nextInt(columnCount));
+  }
+
+  @Override
+  public List<ModelElement> getState(Position position) {
+    List<ModelElement> result = new ArrayList<>();
+    for (Position firefighterPosition : firefighterPositions)
+      if (firefighterPosition.equals(position))
+        result.add(ModelElement.FIREFIGHTER);
+    if (firePositions.contains(position))
+      result.add(ModelElement.FIRE);
+    return result;
+  }
+
+  @Override
+  public int rowCount() {
+    return rowCount;
+  }
+
+  @Override
+  public int columnCount() {
+    return columnCount;
+  }
+
+  public List<Position> updateToNextGeneration() {
+    List<Position> modifiedPositions = updateFirefighters();
+    modifiedPositions.addAll(updateFires());
+    step++;
+    return modifiedPositions;
+  }
+
+  private List<Position> updateFires() {
+    List<Position> modifiedPositions = new ArrayList<>();
+    if (step % 2 == 0) {
+      List<Position> newFirePositions = new ArrayList<>();
+      for (Position fire : firePositions) {
+        newFirePositions.addAll(neighbors.get(fire));
+      }
+      firePositions.addAll(newFirePositions);
+      modifiedPositions.addAll(newFirePositions);
+    }
+    return modifiedPositions;
+
+  }
+
+  @Override
+  public int stepNumber() {
+    return step;
+  }
+
+  private List<Position> updateFirefighters() {
+    List<Position> modifiedPosition = new ArrayList<>();
+    List<Position> firefighterNewPositions = new ArrayList<>();
+    for (Position firefighterPosition : firefighterPositions) {
+      Position newFirefighterPosition =
+              targetStrategy.neighborClosestToFire(firefighterPosition,
+                      firePositions, neighbors);
+      firefighterNewPositions.add(newFirefighterPosition);
+      extinguish(newFirefighterPosition);
+      modifiedPosition.add(firefighterPosition);
+      modifiedPosition.add(newFirefighterPosition);
+      List<Position> neighborFirePositions = neighbors.get(newFirefighterPosition).stream()
+              .filter(firePositions::contains).toList();
+      for (Position firePosition : neighborFirePositions)
+        extinguish(firePosition);
+      modifiedPosition.addAll(neighborFirePositions);
+    }
+    firefighterPositions = firefighterNewPositions;
+    return modifiedPosition;
+  }
+
+  @Override
+  public void reset() {
+    step = 0;
+    initializeElements();
+  }
+
+  private void extinguish(Position position) {
+    firePositions.remove(position);
+  }
+
+
+  @Override
+  public void setState(List<ModelElement> state, Position position) {
+    firePositions.remove(position);
+    for (; ; ) {
+      if (!firefighterPositions.remove(position)) break;
+    }
+    for (ModelElement element : state) {
+      switch (element) {
+        case FIRE -> firePositions.add(position);
+        case FIREFIGHTER -> firefighterPositions.add(position);
+      }
+    }
+  }
+}
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