import java.util.*; public class SnakeEatFood { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); while (scanner.hasNext()) { //输入第 1行为空格分隔的字母，代表贪吃蛇的移动操作。字母取值为 U、D、L、R、G， // 其中U、D、L、R分别表示贪吃蛇往上、下、左、右转向，转向时贪吃蛇不移动， // G表示贪吃蛇按 当前的方向移动一格。用例保证输入的操作正确 String operators = scanner.nextLine(); //第 2行为空格分隔的两个数，指定为 N和 M，为数组的行和列数。 String rowColumInt = scanner.nextLine(); Deque<path> snake = new LinkedList<>(); String[][] gamePanel = gameInitiualize(rowColumInt, scanner, snake); snakeOperate(gamePanel, operators, snake); } } /** * 贪吃蛇游戏面板初始化 * 第 2行为空格分隔的两个数，指定为 N和 M，为数组的行和列数。 * * 余下 N行每行是空格分 隔的 M个字母。字母取值为 H、F和 E，H表示贪吃蛇的起始位置， * F表示食物，E表示该 方格为空。用例保证有且只有一个 H，而 F和 E会有多个 * * @param rowColumInt * @param scanner * @param snake * @return */ private static String[][] gameInitiualize(String rowColumInt, Scanner scanner, Deque<path> snake) { if (rowColumInt == null || "".equals(rowColumInt.trim())) { return null; } String[] rowColum = rowColumInt.split(" "); if (rowColum.length != 2) { return null; } int n = Integer.valueOf(rowColum[0]), m = Integer.valueOf(rowColum[1]); String[][] gamePanel = new String[n][m]; for (int i = 0; i < n; i++) { String temp = scanner.nextLine(); if (temp == null || "".equals(temp.trim())) { continue; } String[] basePoints = temp.split(" "); for (int j = 0; j < m; j++) { if (j > basePoints.length) { continue; } if ("H".equals(basePoints[j])) { snake.addLast(new Path(i, j, "L")); } gamePanel[i][j] = basePoints[j]; } } return gamePanel; } /** * 输入第 1行为空格分隔的字母，代表贪吃蛇的移动操作。字母取值为 U、D、L、R、G， * 其中U、D、L、R分别表示贪吃蛇往上、下、左、右转向，转向时贪吃蛇不移动， * G表示贪吃蛇按 当前的方向移动一格。用例保证输入的操作正确 */ private static void snakeOperate(String[][] gamePanel, String operators, Deque<path> snake) { if (gamePanel == null || operators == null || "".equals(operators.trim()) || snake.isEmpty()) { return; } String[] operations = operators.split(" "); if (operations.length <= 0) { return; } for (String operation : operations) { if ("U".equals(operation)) { snake.getFirst().setDirection("U"); } else if ("D".equals(operation)) { snake.getFirst().setDirection("D"); } else if ("L".equals(operation)) { snake.getFirst().setDirection("L"); } else if ("R".equals(operation)) { snake.getFirst().setDirection("R"); } else { //G //移动 boolean gameOver = move(gamePanel, snake); if (gameOver) { break; } } } } /** * 其中U、D、L、R分别表示贪吃蛇往上、下、左、右转向，转向时贪吃蛇不移动， * G表示贪吃蛇按 当前的方向移动一格 * * @param gamePanel * @param snakes */ public static boolean move(String[][] gamePanel, Deque<path> snakes) { //蛇头 Path snakeHead = snakes.getFirst(); String direction = snakeHead.getDirection(); int row = snakeHead.row, colum = snakeHead.column; switch (direction) { //向上 case "U": row = snakeHead.getRow() - 1; break; case "L": //向左 colum = snakeHead.getColumn() - 1; break; case "R": //向右 colum = snakeHead.getColumn() + 1; break; case "D": //向下 row = snakeHead.getRow() + 1; break; default: break; } //越界,游戏结束 if (row > gamePanel.length - 1 || colum > gamePanel[0].length - 1) { System.out.println(snakes.size()); return true; } //碰到自己了 Iterator<path> snakeItr = snakes.iterator(); while (snakeItr.hasNext()) { Path snakeNode = snakeItr.next(); if (row == snakeNode.getRow() && colum == snakeNode.getColumn()) { System.out.println(snakes.size()); return true; } } //碰到食物了 if ("F".equals(gamePanel[row][colum])) { snakes.addLast(newSnakeNodeInLast(snakes.getLast(), snakes.getLast().direction)); } //正常运动 snakeItr = snakes.iterator(); while (snakeItr.hasNext()) { Path snakeNode = snakeItr.next(); setMovePosition(snakeNode, snakeNode.getDirection(), snakeHead); } return false; } /** * U、D、L、R分别表示贪吃蛇往上、下、左、右转向，转向时贪吃蛇不移动， * @param lastSnakeNode * @param direction * @return */ private static Path newSnakeNodeInLast(Path lastSnakeNode, String direction) { if (null == lastSnakeNode) { return null; } switch (lastSnakeNode.getDirection()) { case "U": //向上 return new Path(lastSnakeNode.row + 1, lastSnakeNode.column, lastSnakeNode.getDirection()); case "L": //向左 return new Path(lastSnakeNode.row, lastSnakeNode.column + 1, lastSnakeNode.getDirection()); case "R": //向右 return new Path(lastSnakeNode.row, lastSnakeNode.column - 1, lastSnakeNode.getDirection()); case "D": //向下 return new Path(lastSnakeNode.row-1, lastSnakeNode.column, lastSnakeNode.getDirection()); default: break; } return null; } private static void setMovePosition(Path snakeNode, String direction, Path snakeHead) { switch (direction) { //向上 case "U": snakeNode.setRow(snakeNode.getRow() - 1); break; case "L": //向左 snakeNode.setColumn(snakeNode.getColumn() - 1); break; case "R": //向右 snakeNode.setColumn(snakeNode.getColumn() + 1); break; case "D": //向下 snakeNode.setRow(snakeNode.getRow() + 1); break; default: break; } snakeNode.setDirection(direction); if (snakeNode.equals(snakeHead)) { return; } //后面的蛇尾进行调整 //与舌头方向一致则不需要重新调整 if (snakeNode.getDirection().equals(snakeHead.getDirection())) { return; } switch (snakeHead.getDirection()) { //向上 case "U": case "D": //向下 snakeNode.setDirection(snakeNode.column == snakeHead.column ? snakeHead.direction : snakeNode.direction); break; case "L": case "R": //向右 //向左 snakeNode.setDirection(snakeNode.row == snakeHead.row ? snakeHead.direction : snakeNode.direction); break; default: break; } } } class Path { int row; int column; String direction; public Path(int row, int column, String direction) { this.row = row; this.column = column; this.direction = direction; } public int getRow() { return row; } public void setRow(int row) { this.row = row; } public int getColumn() { return column; } public void setColumn(int column) { this.column = column; } public String getDirection() { return direction; } public void setDirection(String direction) { this.direction = direction; } }</path></path></path></path></path>