[英]Java Recursive Maze Solver problems
我正在尝试使用递归编写一个迷宫求解器,似乎它尝试了每个方向一次,然后停止并且我不知道为什么。 如果您发现问题,请告诉我。 钥匙0是一个开放空间1是墙壁2是路径的一部分3是迷宫的末端
public class Maze{
public static void main(String[] args){
int[][] maze =
{{1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},
{0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,1},
{1,0,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1,1,1,0,1,0,1},
{1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,1,0,1},
{1,0,1,0,1,1,1,0,1,0,1,1,1,1,1,1,1,1,1,0,1,0,1,1,1,0,1,0,1,1,1,1,1,0,1,1,1,0,1,0,1,0,1,1,1,0,1,1,1,0,1},
{1,0,1,0,1,0,1,0,1,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,1,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,1,0,0,0,0,0,1,0,0,0,1},
{1,0,1,1,1,0,1,0,1,1,1,0,1,0,1,0,1,0,1,1,1,1,1,0,1,0,1,0,1,1,1,0,1,1,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1,0,1},
{1,0,0,0,0,0,1,0,0,0,0,0,1,0,1,0,1,0,1,0,0,0,0,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,1,0,1},
{1,1,1,0,1,1,1,1,1,1,1,1,1,0,1,0,1,0,1,0,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1,0,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1},
{1,0,1,0,1,0,0,0,0,0,0,0,1,0,1,0,1,0,1,0,1,0,0,0,1,0,0,0,0,0,0,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,1,0,0,0,1},
{1,0,1,0,1,0,1,1,1,1,1,0,1,0,1,0,1,1,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,0,1,0,1,1,1,0,1,0,1,1,1},
{1,0,1,0,1,0,0,0,1,0,1,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,1},
{1,0,1,0,1,1,1,0,1,0,1,0,1,0,1,1,1,1,1,1,1,0,1,0,1,0,1,1,1,0,1,1,1,0,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1},
{1,0,1,0,1,0,1,0,1,0,0,0,1,0,1,0,0,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1},
{1,0,1,0,1,0,1,0,1,0,1,1,1,0,1,0,1,1,1,1,1,1,1,1,1,0,1,0,1,1,1,0,1,1,1,0,1,1,1,1,1,0,1,0,1,1,1,1,1,0,1},
{1,0,0,0,1,0,1,0,1,0,0,0,0,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,0,0,1},
{1,0,1,1,1,0,1,0,1,1,1,1,1,1,1,0,1,0,1,1,1,1,1,0,1,1,1,1,1,0,1,0,1,0,1,1,1,0,1,0,1,1,1,1,1,0,1,1,1,0,1},
{1,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,1,0,1,0,0,0,0,0,0,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,1,0,0,0,0,0,1,0,1,0,1},
{1,1,1,1,1,0,1,1,1,0,1,1,1,0,1,0,1,0,1,0,1,1,1,1,1,1,1,0,1,0,1,1,1,1,1,0,1,0,1,0,1,0,1,1,1,1,1,0,1,0,1},
{1,0,0,0,1,0,0,0,1,0,0,0,1,0,1,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,1},
{1,0,1,1,1,1,1,0,1,1,1,0,1,1,1,0,1,0,1,1,1,0,1,0,1,1,1,0,1,1,1,1,1,0,1,0,1,1,1,1,1,1,1,0,1,0,1,0,1,0,1},
{1,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,1,0,1,0,1,0,1},
{1,1,1,0,1,0,1,1,1,0,1,1,1,0,1,0,1,1,1,1,1,0,1,1,1,0,1,1,1,0,1,0,1,0,1,1,1,0,1,0,1,0,1,0,1,0,1,1,1,0,1},
{1,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,1,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,1},
{1,0,1,1,1,0,1,0,1,1,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1,1,1,0,1,0,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,1,0,1,0,1},
{1,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,1},
{1,0,1,1,1,1,1,1,1,0,1,1,1,0,1,1,1,0,1,0,1,0,1,0,1,0,1,1,1,0,1,0,1,0,1,1,1,1,1,0,1,0,1,1,1,0,1,0,1,0,1},
{1,0,0,0,0,0,0,0,1,0,1,0,1,0,1,0,0,0,1,0,1,0,1,0,1,0,0,0,0,0,1,0,1,0,0,0,0,0,1,0,1,0,1,0,0,0,1,0,1,0,1},
{1,0,1,1,1,1,1,0,1,0,1,0,1,0,1,0,1,1,1,0,1,0,1,0,1,0,1,1,1,1,1,0,1,0,1,0,1,1,1,0,1,0,1,0,1,1,1,1,1,0,1},
{1,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,1,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,1,0,1,0,1,0,0,0,1,0,1,0,0,0,0,0,1,0,1},
{1,1,1,1,1,0,1,1,1,1,1,1,1,0,1,0,1,0,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,0,1,1,1,0,1,1,1,0,1,1,1,1,1,0,1,0,1},
{1,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,1,0,1},
{1,0,1,1,1,0,1,1,1,0,1,0,1,1,1,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1,1,1,0,1,0,1,0,1,0,1},
{1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,1,0,0,0,1},
{1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1}};
boolean[][] posCheck = new boolean[maze.length][maze[0].length];
int r = 0;
int c = 0;
for(int row = 0; row < maze.length; row++){
for(int col = 0; col < maze[row].length; col++){
if(maze[row][col]==0){
r = row;
c = col;
}
}
}
maze[r][c] = 3;
mazeSolver(1, 0, 0, maze, posCheck);
}
public static boolean mazeSolver(int r, int c, int d, int[][]maze, boolean[][] posCheck){
maze[r][c] = 2;
if(maze[r][c] == 3){
print(maze);
return true;
}
if((c+1 < maze.length) && maze[r][c+1]==0 && d != 1 && !posCheck[r][c+1]){
if(d != 3)
posCheck[r][c+1] = true;
if(mazeSolver(r, c + 1, 3, maze, posCheck)){
maze[r][c] = 2;
return true;
}
}
if((r-1 >= 0) && maze[r-1][c]==0 && !posCheck[r-1][c] && d != 2){
if(d != 4)
posCheck[r-1][c] = true;
if(mazeSolver(r - 1, c, 4, maze, posCheck)){
maze[r][c] = 2;
return true;
}
}
if((c-1 >= 0) && maze[r][c-1]==0 && !posCheck[r][c-1] && d != 3){
if(d != 1)
posCheck[r][c-1] = true;
if(mazeSolver(r, c - 1, 1, maze, posCheck)){
maze[r][c] = 2;
return true;
}
}
if((r+1 < maze.length) && maze[r+1][c]==0 && !posCheck[r+1][c] && d != 4){
if(d != 2)
posCheck[r+1][c] = true;
if(mazeSolver(r + 1, c, 4, maze, posCheck)){
maze[r][c] = 2;
return true;
}
}
print(maze);
return false;
}
public static void print(int[][] maze){
for(int row = 0; row<maze.length; row++){
for(int col = 0; col<maze[row].length; col++)
System.out.print(maze[row][col]);
System.out.println();
}
}
}
看到您已经接受了答案,但是无论如何我都会添加它...
递归可能是解决某些问题的一种非常优雅的方法,但要花点时间才能解决。 因此,这并不是您的代码为何无法正常工作的确切答案,而更多的是在诸如此类的问题中使用递归的更高层次。
递归问题通常包含两个部分:整体难题状态和与当前尝试相关的状态。 整个递归过程都起作用,因为每次调用递归函数时,都会将一些新状态推入调用堆栈,并且当函数退出时,它将为您删除,因此您可以尝试使用下一个选项。 您还可以在递归函数中操纵整体的拼图状态,但是通常在启动时,我建议您对函数中的拼图状态所做的任何更改都应在退出时恢复。
因此,在您的情况下,迷宫本身是拼图状态,当前路径是对整体拼图状态的临时更改,而当前位置是与当前调用堆栈关联的瞬态。
因此,整体解决方案开始采用以下形式:
// global state
private static int[][] maze;
private static boolean solve(int r, int c) {
// return true if I'm at the exit, false otherwise
}
而main函数只是提供了起始坐标:
public static void main(String[] args) {
if (solve(1, 0)) {
print();
} else {
System.out.println("no solution found");
}
}
因此,下一步是“解决”功能的主体(我已将迷宫数据中的出口位置设置为3-请参阅最后的完整解决方案),其变为:
private static boolean solve(int r, int c) {
if (maze[r][c] == 3) {
// we've found the exit
return true;
}
// push the current position onto the path
maze[r][c] == 2;
// try up / down / left / right - if any of these return true then we're done
if (available(r - 1, c) && solve(r - 1, c)) {
return true;
}
if (available(r + 1, c) && solve(r + 1, c)) {
return true;
}
if (available(r, c - 1) && solve(r, c - 1)) {
return true;
}
if (available(r, c + 1) && solve(r, c + 1)) {
return true;
}
// no result found from the current position so return false
// ... but have to revert the temporary state before doing so
maze[r][c] = 0;
return false;
}
首先检查是否在出口处的简单情况,如果是,则返回true。 如果没有,我们将当前单元格推到路径上,并寻找可用的邻居。 如果找到一个,我们将依次尝试每个,这是递归的核心...如果没有可用的邻居工作,则说明我们失败了,必须回溯。
最后,如果要回溯,则必须从路径中删除当前单元格。
就是这样。 “可用”功能仅检查潜在单元格是否在边界内,而不是在当前路径上是否在墙壁上:
private static boolean available(int r, int c) {
return r >= 0 && r < maze.length
&& c >= 0 && c < maze[r].length
&& (maze[r][c] == 0 || maze[r][c] == 3);
}
完整代码:
public class Maze2 {
private static int[][] maze =
{{1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},
{0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,1},
{1,0,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1,1,1,0,1,0,1},
{1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,1,0,1},
{1,0,1,0,1,1,1,0,1,0,1,1,1,1,1,1,1,1,1,0,1,0,1,1,1,0,1,0,1,1,1,1,1,0,1,1,1,0,1,0,1,0,1,1,1,0,1,1,1,0,1},
{1,0,1,0,1,0,1,0,1,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,1,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,1,0,0,0,0,0,1,0,0,0,1},
{1,0,1,1,1,0,1,0,1,1,1,0,1,0,1,0,1,0,1,1,1,1,1,0,1,0,1,0,1,1,1,0,1,1,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1,0,1},
{1,0,0,0,0,0,1,0,0,0,0,0,1,0,1,0,1,0,1,0,0,0,0,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,1,0,1},
{1,1,1,0,1,1,1,1,1,1,1,1,1,0,1,0,1,0,1,0,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1,0,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1},
{1,0,1,0,1,0,0,0,0,0,0,0,1,0,1,0,1,0,1,0,1,0,0,0,1,0,0,0,0,0,0,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,1,0,0,0,1},
{1,0,1,0,1,0,1,1,1,1,1,0,1,0,1,0,1,1,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,0,1,0,1,1,1,0,1,0,1,1,1},
{1,0,1,0,1,0,0,0,1,0,1,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,1},
{1,0,1,0,1,1,1,0,1,0,1,0,1,0,1,1,1,1,1,1,1,0,1,0,1,0,1,1,1,0,1,1,1,0,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1},
{1,0,1,0,1,0,1,0,1,0,0,0,1,0,1,0,0,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1},
{1,0,1,0,1,0,1,0,1,0,1,1,1,0,1,0,1,1,1,1,1,1,1,1,1,0,1,0,1,1,1,0,1,1,1,0,1,1,1,1,1,0,1,0,1,1,1,1,1,0,1},
{1,0,0,0,1,0,1,0,1,0,0,0,0,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,0,0,1},
{1,0,1,1,1,0,1,0,1,1,1,1,1,1,1,0,1,0,1,1,1,1,1,0,1,1,1,1,1,0,1,0,1,0,1,1,1,0,1,0,1,1,1,1,1,0,1,1,1,0,1},
{1,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,1,0,1,0,0,0,0,0,0,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,1,0,0,0,0,0,1,0,1,0,1},
{1,1,1,1,1,0,1,1,1,0,1,1,1,0,1,0,1,0,1,0,1,1,1,1,1,1,1,0,1,0,1,1,1,1,1,0,1,0,1,0,1,0,1,1,1,1,1,0,1,0,1},
{1,0,0,0,1,0,0,0,1,0,0,0,1,0,1,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,1},
{1,0,1,1,1,1,1,0,1,1,1,0,1,1,1,0,1,0,1,1,1,0,1,0,1,1,1,0,1,1,1,1,1,0,1,0,1,1,1,1,1,1,1,0,1,0,1,0,1,0,1},
{1,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,1,0,1,0,1,0,1},
{1,1,1,0,1,0,1,1,1,0,1,1,1,0,1,0,1,1,1,1,1,0,1,1,1,0,1,1,1,0,1,0,1,0,1,1,1,0,1,0,1,0,1,0,1,0,1,1,1,0,1},
{1,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,1,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,1},
{1,0,1,1,1,0,1,0,1,1,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1,1,1,0,1,0,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,1,0,1,0,1},
{1,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,1},
{1,0,1,1,1,1,1,1,1,0,1,1,1,0,1,1,1,0,1,0,1,0,1,0,1,0,1,1,1,0,1,0,1,0,1,1,1,1,1,0,1,0,1,1,1,0,1,0,1,0,1},
{1,0,0,0,0,0,0,0,1,0,1,0,1,0,1,0,0,0,1,0,1,0,1,0,1,0,0,0,0,0,1,0,1,0,0,0,0,0,1,0,1,0,1,0,0,0,1,0,1,0,1},
{1,0,1,1,1,1,1,0,1,0,1,0,1,0,1,0,1,1,1,0,1,0,1,0,1,0,1,1,1,1,1,0,1,0,1,0,1,1,1,0,1,0,1,0,1,1,1,1,1,0,1},
{1,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,1,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,1,0,1,0,1,0,0,0,1,0,1,0,0,0,0,0,1,0,1},
{1,1,1,1,1,0,1,1,1,1,1,1,1,0,1,0,1,0,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,0,1,1,1,0,1,1,1,0,1,1,1,1,1,0,1,0,1},
{1,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,1,0,1},
{1,0,1,1,1,0,1,1,1,0,1,0,1,1,1,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1,1,1,0,1,0,1,0,1,0,1},
{1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,1,0,0,0,1},
{1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,3,1}};
public static void main(String[] args) {
if (solve(1, 0)) {
print();
} else {
System.out.println("no solution found");
}
}
private static boolean solve(int r, int c) {
// if we're at the goal then we've solved it
if (maze[r][c] == 3) {
return true;
}
// mark the current cell as on the path
maze[r][c] = 2;
// try all available neighbours - if any of these return true then we're solved
if (available(r - 1, c) && solve(r - 1, c)) {
return true;
}
if (available(r + 1, c) && solve(r + 1, c)) {
return true;
}
if (available(r, c - 1) && solve(r, c - 1)) {
return true;
}
if (available(r, c + 1) && solve(r, c + 1)) {
return true;
}
// nothing found so remove the current cell from the path and backtrack
maze[r][c] = 0;
return false;
}
// cell is available if it is in the maze and either a clear space or the
// goal - it is not available if it is a wall or already on the current path
private static boolean available(int r, int c) {
return r >= 0 && r < maze.length
&& c >= 0 && c < maze[r].length
&& (maze[r][c] == 0 || maze[r][c] == 3);
}
// use symbols to make reading the output easier...
private static final char[] SYMBOLS = {' ', '#', '.', '*' };
private static void print(){
for(int row = 0; row < maze.length; ++row) {
for(int col = 0; col < maze[row].length; ++col) {
System.out.print(SYMBOLS[maze[row][col]]);
}
System.out.println();
}
}
}
最后,如果要打印出所有可能的解决方案,而不仅仅是找到的第一个解决方案,则只需将已解决函数的顶部更改为:
// if we're at the goal then print it but return false to continue searching
if (maze[r][c] == 3) {
print();
return false;
}
快乐递归!
在过去五个小时中,您已经问过有关此迷宫递归难题的四个问题,这证明它有多复杂。 这整个概念的1/0迷宫电网已吸引了我,我想出了一个类,应该让一大堆简单。 如果需要进行递归,那么它将对您没有用,但是如果您可以使用它,那么它将消除很多复杂性。
有两个类,一个枚举。
首先,枚举定义要在网格中移动的方向,并基于其移动一次确定新索引。
enum Direction {
UP(-1, 0),
DOWN(1, 0),
LEFT(0, -1),
RIGHT(0, 1);
private final int rowSteps;
private final int colSteps;
private Direction(int rowSteps, int colSteps) {
this.rowSteps = rowSteps;
this.colSteps = colSteps;
}
public int getNewRowIdx(int currentRowIdx) {
return (currentRowIdx + getRowSteps());
}
public int getNewColIdx(int currentColIdx) {
return (currentColIdx + getColSteps());
}
public int getRowSteps() {
return rowSteps;
}
public int getColSteps() {
return colSteps;
}
};
主要类称为MazePosition
(下)。 首先,通过其int[][]
构造函数在其中设置迷宫网格双数组,并静态存储该实例:
private static final MazePosition MAZE_HOLDER = new MazePosition(MAZE_GRID);
(可以将这一步骤设计得更好,但是可以。)
设置迷宫网格(每次执行时,这是一次性的事情)后,然后使用x / y构造函数声明初始位置:
MazePosition pos = new MazePosition(0, 0);
然后,根据需要移动:
pos = pos.getNeighbor(Direction.RIGHT);
pos = pos.getNeighbor(Direction.RIGHT);
pos = pos.getNeighbor(Direction.DOWN);
...
每个位置的值由pos.getValue()
或pos.isPath()
检索-我认为1
是“墙”, 0
是“路径”。 (顺便说一句:巨大的2d数组实际上应该包含一个booleans
,而不是4字节的ints
,但是查看数组的代码对int
有意义,而对booleans则不行。请注意,它应该至少更改为byte
s。)
因此,关于移动,如果您尝试在没有邻居时获得邻居,例如在左边缘向左移动,则会引发IllegalStateException
。 使用is*Edge()
函数可以避免这种情况。
MazePosition类还有一个方便的调试函数,称为getNineByNine()
,该函数返回9x9的数组值网格(作为字符串),其中中间项是当前位置。
import java.util.Arrays;
import java.util.Objects;
class MazePosition {
//state
private static int[][] MAZE_GRID;
private final int rowIdx;
private final int colIdx;
//internal
private final int rowIdxMinus1;
private final int colIdxMinus1;
public MazePosition(int[][] MAZE_GRID) {
if(this.MAZE_GRID != null) {
throw new IllegalStateException("Maze double-array already set. Use x/y constructor.");
}
MazePosition.MAZE_GRID = MAZE_GRID;
//TODO: Crash if null or empty, or sub-arrays null or empty, or unequal lengths, or contain anything but 0 or -1.
rowIdx = -1;
colIdx = -1;
rowIdxMinus1 = -1;
colIdxMinus1 = -1;
}
public MazePosition(int rowIdx, int colIdx) {
if(MazePosition.MAZE_GRID == null) {
throw new IllegalStateException("Must set maze double-array with: new MazePosition(int[][]).");
}
if(rowIdx < 0 || rowIdx >= MazePosition.getRowCount()) {
throw new IllegalArgumentException("rowIdx (" + rowIdx + ") is invalid.");
}
if(colIdx < 0 || colIdx >= MazePosition.getColumnCount()) {
throw new IllegalArgumentException("colIdx (" + colIdx + ") is invalid.");
}
this.rowIdx = rowIdx;
this.colIdx = colIdx;
rowIdxMinus1 = (rowIdx - 1);
colIdxMinus1 = (colIdx - 1);
}
public boolean isPath() {
return (getValue() == 0); //1???
}
public int getValue() {
return MazePosition.MAZE_GRID[getRowIdx()][getColumnIdx()];
}
public int getRowIdx() {
return rowIdx;
}
public int getColumnIdx() {
return colIdx;
}
public MazePosition getNeighbor(Direction dir) {
Objects.requireNonNull(dir, "dir");
return (new MazePosition(
dir.getNewRowIdx(getRowIdx()),
dir.getNewColIdx(getColumnIdx())));
}
public MazePosition getNeighborNullIfEdge(Direction dir) {
if(isEdgeForDirection(dir)) {
return null;
}
return getNeighbor(dir);
}
public int getNeighborValueNeg1IfEdge(Direction dir) {
MazePosition pos = getNeighborNullIfEdge(dir);
return ((pos == null) ? -1 : pos.getValue());
}
public static final int getRowCount() {
return MAZE_GRID.length;
}
public static final int getColumnCount() {
return MAZE_GRID[0].length;
}
public boolean isEdgeForDirection(Direction dir) {
Objects.requireNonNull(dir);
switch(dir) {
case UP: return isTopEdge();
case DOWN: return isBottomEdge();
case LEFT: return isLeftEdge();
case RIGHT: return isRightEdge();
}
throw new IllegalStateException(toString() + ", dir=" + dir);
}
public boolean isLeftEdge() {
return (getColumnIdx() == 0);
}
public boolean isTopEdge() {
return (getRowIdx() == 0);
}
public boolean isBottomEdge() {
return (getRowIdx() == rowIdxMinus1);
}
public boolean isRightEdge() {
return (getColumnIdx() == colIdxMinus1);
}
public String toString() {
return "[" + getRowIdx() + "," + getColumnIdx() + "]=" + getValue();
}
public String getNineByNine() {
int[][] nineByNine = new int[3][3];
//Middle row
nineByNine[1][1] = getValue();
nineByNine[1][0] = getNeighborValueNeg1IfEdge(Direction.LEFT);
nineByNine[1][2] = getNeighborValueNeg1IfEdge(Direction.RIGHT);
//Top
MazePosition posUp = getNeighborNullIfEdge(Direction.UP);
if(posUp != null) {
nineByNine[0][0] = posUp.getNeighborValueNeg1IfEdge(Direction.LEFT);
nineByNine[0][1] = posUp.getValue();
nineByNine[0][2] = posUp.getNeighborValueNeg1IfEdge(Direction.RIGHT);
}
//Bottom
MazePosition posDown = getNeighborNullIfEdge(Direction.DOWN);
if(posDown != null) {
nineByNine[2][0] = posDown.getNeighborValueNeg1IfEdge(Direction.LEFT);
nineByNine[2][1] = posDown.getValue();
nineByNine[2][2] = posDown.getNeighborValueNeg1IfEdge(Direction.RIGHT);
}
String sLS = System.getProperty("line.separator", "\r\n");
return "Middle position in 9x9 grid is *this*: " + toString() + sLS +
Arrays.toString(nineByNine[0]) + sLS +
Arrays.toString(nineByNine[1]) + sLS +
Arrays.toString(nineByNine[2]);
}
}
它所没有的是“碰撞检测”或任何真正为您找到迷宫路径的东西。 它只是在整个网格中移动,无论它是否穿过墙壁。 可以很容易地添加一些getNeighborIfNotWall(Direction)
和isWallToLeft()
函数,但我将留给您。 ;)
(实际上,这些类无需进行太多更改,就可以用于遍历任何2D数组,尽管我可能会添加对角线方向(例如UP_LEFT
)以及移动多个步骤的能力,例如getNeighbor(3, Direction.DOWN)
)。
这是一个演示用法:
public class MazePosDemo {
private static final int[][] MAZE_GRID = new int[][] {
//mega maze grid goes here...
};
private static final MazePosition MAZE_HOLDER = new MazePosition(MAZE_GRID);
public static final void main(String[] ignored) {
MazePosition pos = new MazePosition(0, 0);
System.out.println("start: " + pos);
pos = pos.getNeighbor(Direction.RIGHT);
System.out.println("right: " + pos);
pos = pos.getNeighbor(Direction.RIGHT);
System.out.println("right: " + pos);
pos = pos.getNeighbor(Direction.DOWN);
System.out.println("down: " + pos);
pos = pos.getNeighbor(Direction.DOWN);
System.out.println("down: " + pos);
pos = pos.getNeighbor(Direction.RIGHT);
System.out.println("right: " + pos);
pos = pos.getNeighbor(Direction.DOWN);
System.out.println("down: " + pos);
pos = pos.getNeighbor(Direction.LEFT);
System.out.println("left: " + pos);
pos = pos.getNeighbor(Direction.UP);
System.out.println("up: " + pos);
pos = pos.getNeighbor(Direction.UP);
System.out.println("up: " + pos);
System.out.println(pos.getNineByNine());
}
}
输出量
[C:\java_code\]java MazePosDemo
start: [0,0]=1
right: [0,1]=1
right: [0,2]=1
down: [1,2]=1
down: [2,2]=1
right: [2,3]=1
down: [3,3]=0
left: [3,2]=1
up: [2,2]=1
up: [1,2]=1
Middle position in 9x9 grid is *this*: [1,2]=1
[1, 1, 1]
[0, 1, 0]
[0, 1, 1]
这是完整的源代码文件,其中包含上述所有内容(包括mega-maze-array):
//Needed only by MazePosition
import java.util.Arrays;
import java.util.Objects;
enum Direction {
UP(-1, 0),
DOWN(1, 0),
LEFT(0, -1),
RIGHT(0, 1);
//config
private final int rowSteps;
private final int colSteps;
private Direction(int rowSteps, int colSteps) {
this.rowSteps = rowSteps;
this.colSteps = colSteps;
}
public int getNewRowIdx(int currentRowIdx) {
return (currentRowIdx + getRowSteps());
}
public int getNewColIdx(int currentColIdx) {
return (currentColIdx + getColSteps());
}
public int getRowSteps() {
return rowSteps;
}
public int getColSteps() {
return colSteps;
}
};
class MazePosition {
//config
private static int[][] MAZE_GRID;
private final int rowIdx;
private final int colIdx;
//internal
private final int rowIdxMinus1;
private final int colIdxMinus1;
public MazePosition(int[][] MAZE_GRID) {
if(this.MAZE_GRID != null) {
throw new IllegalStateException("Maze double-array already set. Use x/y constructor.");
}
MazePosition.MAZE_GRID = MAZE_GRID;
//TODO: Crash if null or empty, or sub-arrays null or empty, or unequal lengths, or contain anything but 0 or -1.
rowIdx = -1;
colIdx = -1;
rowIdxMinus1 = -1;
colIdxMinus1 = -1;
}
public MazePosition(int rowIdx, int colIdx) {
if(MazePosition.MAZE_GRID == null) {
throw new IllegalStateException("Must set maze double-array with: new MazePosition(int[][]).");
}
if(rowIdx < 0 || rowIdx >= MazePosition.getRowCount()) {
throw new IllegalArgumentException("rowIdx (" + rowIdx + ") is invalid.");
}
if(colIdx < 0 || colIdx >= MazePosition.getColumnCount()) {
throw new IllegalArgumentException("colIdx (" + colIdx + ") is invalid.");
}
this.rowIdx = rowIdx;
this.colIdx = colIdx;
rowIdxMinus1 = (rowIdx - 1);
colIdxMinus1 = (colIdx - 1);
}
public boolean isPath() {
return (getValue() == 0); //1???
}
public int getValue() {
return MazePosition.MAZE_GRID[getRowIdx()][getColumnIdx()];
}
public int getRowIdx() {
return rowIdx;
}
public int getColumnIdx() {
return colIdx;
}
public MazePosition getNeighbor(Direction dir) {
Objects.requireNonNull(dir, "dir");
return (new MazePosition(
dir.getNewRowIdx(getRowIdx()),
dir.getNewColIdx(getColumnIdx())));
}
public MazePosition getNeighborNullIfEdge(Direction dir) {
if(isEdgeForDirection(dir)) {
return null;
}
return getNeighbor(dir);
}
public int getNeighborValueNeg1IfEdge(Direction dir) {
MazePosition pos = getNeighborNullIfEdge(dir);
return ((pos == null) ? -1 : pos.getValue());
}
public static final int getRowCount() {
return MAZE_GRID.length;
}
public static final int getColumnCount() {
return MAZE_GRID[0].length;
}
public boolean isEdgeForDirection(Direction dir) {
Objects.requireNonNull(dir);
switch(dir) {
case UP: return isTopEdge();
case DOWN: return isBottomEdge();
case LEFT: return isLeftEdge();
case RIGHT: return isRightEdge();
}
throw new IllegalStateException(toString() + ", dir=" + dir);
}
public boolean isLeftEdge() {
return (getColumnIdx() == 0);
}
public boolean isTopEdge() {
return (getRowIdx() == 0);
}
public boolean isBottomEdge() {
return (getRowIdx() == rowIdxMinus1);
}
public boolean isRightEdge() {
return (getColumnIdx() == colIdxMinus1);
}
public String toString() {
return "[" + getRowIdx() + "," + getColumnIdx() + "]=" + getValue();
}
public String getNineByNine() {
int[][] nineByNine = new int[3][3];
//Middle row
nineByNine[1][1] = getValue();
nineByNine[1][0] = getNeighborValueNeg1IfEdge(Direction.LEFT);
nineByNine[1][2] = getNeighborValueNeg1IfEdge(Direction.RIGHT);
//Top
MazePosition posUp = getNeighborNullIfEdge(Direction.UP);
if(posUp != null) {
nineByNine[0][0] = posUp.getNeighborValueNeg1IfEdge(Direction.LEFT);
nineByNine[0][1] = posUp.getValue();
nineByNine[0][2] = posUp.getNeighborValueNeg1IfEdge(Direction.RIGHT);
}
//Bottom
MazePosition posDown = getNeighborNullIfEdge(Direction.DOWN);
if(posDown != null) {
nineByNine[2][0] = posDown.getNeighborValueNeg1IfEdge(Direction.LEFT);
nineByNine[2][1] = posDown.getValue();
nineByNine[2][2] = posDown.getNeighborValueNeg1IfEdge(Direction.RIGHT);
}
String sLS = System.getProperty("line.separator", "\r\n");
return "Middle position in 9x9 grid is *this*: " + toString() + sLS +
Arrays.toString(nineByNine[0]) + sLS +
Arrays.toString(nineByNine[1]) + sLS +
Arrays.toString(nineByNine[2]);
}
}
public class MazePosDemo {
private static final int[][] MAZE_GRID = new int[][] {
{1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1},
{0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,1},
{1,0,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1,1,1,0,1,0,1},
{1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,1,0,1},
{1,0,1,0,1,1,1,0,1,0,1,1,1,1,1,1,1,1,1,0,1,0,1,1,1,0,1,0,1,1,1,1,1,0,1,1,1,0,1,0,1,0,1,1,1,0,1,1,1,0,1},
{1,0,1,0,1,0,1,0,1,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,1,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,1,0,0,0,0,0,1,0,0,0,1},
{1,0,1,1,1,0,1,0,1,1,1,0,1,0,1,0,1,0,1,1,1,1,1,0,1,0,1,0,1,1,1,0,1,1,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1,0,1},
{1,0,0,0,0,0,1,0,0,0,0,0,1,0,1,0,1,0,1,0,0,0,0,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,1,0,1},
{1,1,1,0,1,1,1,1,1,1,1,1,1,0,1,0,1,0,1,0,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1,0,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1},
{1,0,1,0,1,0,0,0,0,0,0,0,1,0,1,0,1,0,1,0,1,0,0,0,1,0,0,0,0,0,0,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,1,0,0,0,1},
{1,0,1,0,1,0,1,1,1,1,1,0,1,0,1,0,1,1,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,0,1,0,1,1,1,0,1,0,1,1,1},
{1,0,1,0,1,0,0,0,1,0,1,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,1},
{1,0,1,0,1,1,1,0,1,0,1,0,1,0,1,1,1,1,1,1,1,0,1,0,1,0,1,1,1,0,1,1,1,0,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1},
{1,0,1,0,1,0,1,0,1,0,0,0,1,0,1,0,0,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1},
{1,0,1,0,1,0,1,0,1,0,1,1,1,0,1,0,1,1,1,1,1,1,1,1,1,0,1,0,1,1,1,0,1,1,1,0,1,1,1,1,1,0,1,0,1,1,1,1,1,0,1},
{1,0,0,0,1,0,1,0,1,0,0,0,0,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,0,0,1},
{1,0,1,1,1,0,1,0,1,1,1,1,1,1,1,0,1,0,1,1,1,1,1,0,1,1,1,1,1,0,1,0,1,0,1,1,1,0,1,0,1,1,1,1,1,0,1,1,1,0,1},
{1,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,1,0,1,0,0,0,0,0,0,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,1,0,0,0,0,0,1,0,1,0,1},
{1,1,1,1,1,0,1,1,1,0,1,1,1,0,1,0,1,0,1,0,1,1,1,1,1,1,1,0,1,0,1,1,1,1,1,0,1,0,1,0,1,0,1,1,1,1,1,0,1,0,1},
{1,0,0,0,1,0,0,0,1,0,0,0,1,0,1,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,1},
{1,0,1,1,1,1,1,0,1,1,1,0,1,1,1,0,1,0,1,1,1,0,1,0,1,1,1,0,1,1,1,1,1,0,1,0,1,1,1,1,1,1,1,0,1,0,1,0,1,0,1},
{1,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,1,0,1,0,1,0,1},
{1,1,1,0,1,0,1,1,1,0,1,1,1,0,1,0,1,1,1,1,1,0,1,1,1,0,1,1,1,0,1,0,1,0,1,1,1,0,1,0,1,0,1,0,1,0,1,1,1,0,1},
{1,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,1,0,1,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,1},
{1,0,1,1,1,0,1,0,1,1,1,0,1,1,1,0,1,1,1,1,1,1,1,0,1,1,1,0,1,0,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,1,0,1,0,1},
{1,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,1,0,0,0,1,0,1,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,1},
{1,0,1,1,1,1,1,1,1,0,1,1,1,0,1,1,1,0,1,0,1,0,1,0,1,0,1,1,1,0,1,0,1,0,1,1,1,1,1,0,1,0,1,1,1,0,1,0,1,0,1},
{1,0,0,0,0,0,0,0,1,0,1,0,1,0,1,0,0,0,1,0,1,0,1,0,1,0,0,0,0,0,1,0,1,0,0,0,0,0,1,0,1,0,1,0,0,0,1,0,1,0,1},
{1,0,1,1,1,1,1,0,1,0,1,0,1,0,1,0,1,1,1,0,1,0,1,0,1,0,1,1,1,1,1,0,1,0,1,0,1,1,1,0,1,0,1,0,1,1,1,1,1,0,1},
{1,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,1,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,1,0,1,0,1,0,0,0,1,0,1,0,0,0,0,0,1,0,1},
{1,1,1,1,1,0,1,1,1,1,1,1,1,0,1,0,1,0,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,0,1,1,1,0,1,1,1,0,1,1,1,1,1,0,1,0,1},
{1,0,0,0,1,0,1,0,0,0,1,0,0,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,1,0,0,0,1,0,0,0,1,0,1,0,1},
{1,0,1,1,1,0,1,1,1,0,1,0,1,1,1,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1,1,1,0,1,0,1,0,1,0,1},
{1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,1,0,0,0,1},
{1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1}};
private static final MazePosition MAZE_HOLDER = new MazePosition(MAZE_GRID);
public static final void main(String[] ignored) {
MazePosition pos = new MazePosition(0, 0);
System.out.println("start: " + pos);
pos = pos.getNeighbor(Direction.RIGHT);
System.out.println("right: " + pos);
pos = pos.getNeighbor(Direction.RIGHT);
System.out.println("right: " + pos);
pos = pos.getNeighbor(Direction.DOWN);
System.out.println("down: " + pos);
pos = pos.getNeighbor(Direction.DOWN);
System.out.println("down: " + pos);
pos = pos.getNeighbor(Direction.RIGHT);
System.out.println("right: " + pos);
pos = pos.getNeighbor(Direction.DOWN);
System.out.println("down: " + pos);
pos = pos.getNeighbor(Direction.LEFT);
System.out.println("left: " + pos);
pos = pos.getNeighbor(Direction.UP);
System.out.println("up: " + pos);
pos = pos.getNeighbor(Direction.UP);
System.out.println("up: " + pos);
System.out.println(pos.getNineByNine());
}
}
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