improved Snake2, singlefile no classes simplified & functional

other/Snake/src/Snake2.java

@@ -1,3 +1,157 @@
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.util.ArrayList;
+import java.util.Scanner;
+
+import static java.lang.System.out;
+
+class Coordinate
+{
+    public int x;
+    public int y;
+
+    public Coordinate()
+    {
+        this(0, 0);
+    }
+
+    public Coordinate(int x, int y)
+    {
+        this.x = x;
+        this.y = y;
+    }
+
+    public Coordinate plus(Coordinate other)
+    {
+        return new Coordinate(this.x + other.x, this.y + other.y);
+    }
+
+    public boolean equals(Coordinate other)
+    {
+        return this.x == other.x && this.y == other.y;
+    }
+
+    @Override
+    public String toString()
+    {
+        return String.format("(%s, %s)", this.x, this.y);
+    }
+}
+
+
 public class Snake2
 {
+    private static final Coordinate UP = new Coordinate(0, -1);
+    private static final Coordinate DOWN = new Coordinate(0, 1);
+    private static final Coordinate LEFT = new Coordinate(-1, 0);
+    private static final Coordinate RIGHT = new Coordinate(1, 0);
+
+    public static void main(String[] args) throws FileNotFoundException
+    {
+        // Read in board input
+        char[][] board = new char[15][15];
+        Scanner input = new Scanner(new File("./src/snake2.dat"));
+        for (int y = 0; y < 15; y++) {
+            String line = input.nextLine();
+            for (int x = 0; x < 15; x++)
+                // If the line was cut short, fill with spaces
+                if (line.length() >= x + 1)
+                    board[y][x] = line.charAt(x);
+                else
+                    board[y][x] = ' ';
+        }
+
+        input.nextLine();
+        // Use all inputs and simulate Snake
+        while (input.hasNextLine()) {
+            // copy the original board
+            char[][] copyBoard = new char[15][15];
+            for (int y = 0; y < 15; y++)
+                copyBoard[y] = board[y].clone();
+            simulate(copyBoard, input.nextLine());
+        }
+    }
+
+    public static void simulate(char[][] board, String commands)
+    {
+        Coordinate snakeHead = null;
+        // Scan for the snake from top to bottom, right to left
+        for (int y = 14; y >= 0; y--) {
+            for (int x = 14; x >= 0; x--) {
+                if (board[y][x] == 'X') {
+                    snakeHead = new Coordinate(x, y);
+                    board[y][x] = ' ';
+                    break;
+                }
+            }
+            if (snakeHead != null)
+                break;
+        }
+
+        // Initialize simulation variables
+        ArrayList<Coordinate> snake = new ArrayList<Coordinate>();
+        Coordinate previousMove = RIGHT; // moves to the RIGHT by default
+        Coordinate currentMove = null;
+        boolean gameover = false;
+        int pellets = 0;
+
+        // Add initial snake positions
+        assert snakeHead != null;
+        snake.add(snakeHead); // Snake head is always the right most, and starts 3 nodes long
+        snake.add(snakeHead.plus(new Coordinate(-1, 0)));
+        snake.add(snakeHead.plus(new Coordinate(-2, 0)));
+
+        // Parse each character command into a coordinate movement
+        for (char command : commands.toCharArray()) {
+            switch (command) {
+                case 'L':
+                    currentMove = LEFT;
+                    break;
+                case 'R':
+                    currentMove = RIGHT;
+                    break;
+                case 'U':
+                    currentMove = UP;
+                    break;
+                case 'D':
+                    currentMove = DOWN;
+                    break;
+                case 'O':
+                    currentMove = previousMove;
+                    break;
+            }
+            previousMove = currentMove;
+            Coordinate newPosition = snake.get(0).plus(currentMove);
+
+            // Test if new move is outside boundaries or if the snake contains the new position
+            if (newPosition.x < 0 || newPosition.y < 0 || newPosition.x >= 15 || newPosition.y >= 15 || snake.contains(newPosition)) {
+                gameover = true;
+                break;
+            }
+
+            // 'Move' the snake by adding new position, popping tail once
+            snake.add(0, newPosition);
+
+            // Check if pellet can be eaten, if not, pop off tail
+            if (board[newPosition.y][newPosition.x] == 'F') {
+                pellets++;
+                board[newPosition.y][newPosition.x] = ' ';
+            } else {
+                snake.remove(snake.size() - 1);
+            }
+        }
+
+        // Print game's end status
+        if (gameover)
+            out.println("GAME OVER");
+        else
+            out.println(String.format("%d pellets", pellets));
+
+        // Print game board
+        for (Coordinate node : snake) {
+            board[node.y][node.x] = 'X';
+        }
+        for (char[] line : board)
+            out.println(line);
+    }
 }