EscapeBot with Breadth-First-Search

escapetest.sh

@@ -0,0 +1,4 @@
+while true
+do
+docker run --rm -p 63187:63187 mediaeng/bots escape
+done

src/EscapeBot.java

@@ -1,7 +1,11 @@
+import java.util.LinkedList;
+import java.util.Queue;
+
 public class EscapeBot extends Bot {
-    boolean offByOne = true;
+    protected final static String obstacles = "~#X*";
-    int currentStepCount = 0;
+    protected boolean offByOne = true;
-    int steps = 0;
+    protected int currentStepCount = 0;
+    protected int steps = 0;
 
     public static void main(String[] args) {
         Bot bot = new EscapeBot(args);
@@ -15,27 +19,87 @@ public class EscapeBot extends Bot {
     @Override
     protected char nextMove(View view) {
         System.out.println();
-        if (view.data.contains("o")) {
+        String data = view.data
-            int index = view.data.indexOf('o');
+                .replace('^', '*')
-            if (index < view.width * 2 && !(index > view.width * 3)) {
+                .replace('<', '*')
-                return '^';
+                .replace('>', '*')
-            } else if (index % 5 < 2) {
+                .replace('v', '*');
-                return '<';
+        char[][] grid = dataToGrid(data, view.width);
-            } else if (index % 5 > 2) {
+
-                return '>';
+        if (data.contains("o")) {
+            return breadthFirstSearch(grid);
+        } else {
+            return walkAround(grid);
         }
-            return ' ';
+    }
-        } else if (steps == 0) {
+
-            currentStepCount += 1;
+    protected char[][] dataToGrid(String data, int size) {
+        char[][] grid = new char[size][size];
+        for (int i = 0; i < data.length(); i++) {
+            grid[i % size][i / size] = data.charAt(i);
+        }
+        return grid;
+    }
+
+    protected char walkAround(char[][] grid) {
+        if (steps == 0) {
+            currentStepCount++;
             if (offByOne) {
-                currentStepCount += 1;
+                currentStepCount++;
             }
             offByOne = !offByOne;
             steps = currentStepCount;
             return '>';
         } else {
-            steps -= 1;
+            steps--;
+            return safeMove(grid);
+        }
+    }
+
+    protected char safeMove(char[][] grid) {
+        int size = grid.length;
+        if (grid[size / 2][size / 2 - 1] == '*') {
+            return '<';
+        } else {
             return '^';
         }
     }
+
+    protected char breadthFirstSearch(char[][] grid) {
+        int size = grid.length;
+        int start = size / 2;
+
+        boolean[][] visited = new boolean[size][size];
+        Queue<Move> queue = new LinkedList<>();
+
+        int[][] directions = {{0, -1}, {0, 1}, {1, 0}, {-1, 0}};
+        char[] commands = {'^', '>', '>', '<'};
+        for (int i = 0; i < 4; i++) {
+            queue.add(new Move(start + directions[i][0], start + directions[i][1], commands[i]));
+        }
+
+        queue.add(new Move(start, start - 1, '^'));
+        queue.add(new Move(start, start + 1, '>'));
+        queue.add(new Move(start + 1, start, '>'));
+        queue.add(new Move(start - 1, start, '<'));
+
+        while (!queue.isEmpty()) {
+            Move move = queue.poll();
+            if (move.x < 0 || move.x >= size || move.y < 0 || move.y >= size || visited[move.x][move.y]) continue;
+            visited[move.x][move.y] = true;
+            if (obstacles.contains("" + grid[move.x][move.y])) continue;
+            if (grid[move.x][move.y] == 'o') return move.direction;
+
+            for (int[] direction : directions) {
+                queue.add(new Move(move.x + direction[0], move.y + direction[1], move.direction));
+            }
+        }
+
+        System.err.println("No path found");
+        return safeMove(grid);
+    }
+
+    protected record Move(int x, int y, char direction) {
+    }
+
 }