import java.awt.Point;
import java.util.ArrayList;

/*回溯法走迷宫
 * 定义一个二维数组：

int maze[5][5] = {

	0, 1, 0, 1, 0,

	0, 1, 0, 1, 0,

	0, 0, 0, 0, 0,

	0, 1, 1, 1, 0,

	0, 0, 0, 1, 0,

};

它表示一个迷宫，其中的1表示墙壁，0表示可以走的路，只能横着走或竖着走，不能斜着走，要求编程序找出从左上角到右下角的最短路线。 

输入:

一个5 × 5的二维数组，表示一个迷宫。数据保证有唯一解。 
输出:

左上角到右下角的最短路径，格式如样例所示。

样例输入:

0 1 0 1 0
0 1 0 1 0
0 0 0 0 0
0 1 1 1 0
0 0 0 1 0

样例输出:

(0, 0)
(1, 0)
(2, 0)
(2, 1)
(2, 2)
(2, 3)
(2, 4)
(3, 4)
(4, 4)
 */

public class Maze {
	 private int[][] maze;
	 private int maxLine= 5;
	 private int maxRow= 5;
	 private ArrayList<Point> list=null;
	 
	 public static void main(String[] args) {
		 new Maze().initialise();
	}
	 private void initialise(){
		 maze=new int[][] {
					{0, 1, 0, 1, 0},
					{0, 1, 0, 1, 0},
					{0, 0, 0, 0, 0},
					{0, 1, 1, 1, 0},
					{0, 0, 0, 1, 0},
				};
		list=new ArrayList<Point>();
		check(0, 0);
		 
	 }
	 private void check(int i,int j){
		 if(i==maxRow-1&&j==maxLine-1)
		 {
			print();
			return;
		 }
		 //向上走
		 if(canMove(i, j, i-1, j)){
			 Point p=new Point(i, j);
			 maze[i][j]=-1;
			 list.add(p);
			 check(i-1, j);
			 maze[i][j]=0;
			 list.remove(p);
		 }
		 //向下走
		 if(canMove(i, j, i+1, j)){
			 Point p=new Point(i, j);
			 maze[i][j]=-1;
			 list.add(p);
			 check(i+1, j);
			 maze[i][j]=0;
			 list.remove(p);
		 }
		 //向左走
		 if(canMove(i, j, i, j-1)){
			 Point p=new Point(i, j);
			 maze[i][j]=-1;
			 list.add(p);
			 check(i, j-1);
			 maze[i][j]=0;
			 list.remove(p);
		 }
		 //向右走
		 if(canMove(i, j, i, j+1)){
			 Point p=new Point(i, j);
			 maze[i][j]=-1;
			 list.add(p);
			 check(i, j+1);
			 maze[i][j]=0;
			 list.remove(p);
		 }
	 }
	 
	 private boolean canMove(int i,int j,int targetI,int targetJ){
		 if(targetI<0||targetJ<0||targetI>maxRow-1||targetJ>maxLine-1)
			 return false;
		 if(maze[targetI][targetJ]==1)
			 return false;
		 if(maze[targetI][targetJ]==-1)
			 return false;
		 return true;
	 }
	 
	 private void print(){
		 for (Point point : list) 
			System.out.println("("+(int)point.getX()+", "+(int)point.getY()+")");
		 System.out.println("(4, 4)");
	 }
}