Java遞歸迷宮求解器問題
[英]Java Recursive Maze Solver problems
問題描述
我正在嘗試使用遞歸編寫一個迷宮求解器，似乎它嘗試了每個方向一次，然后停止並且我不知道為什么。 如果您發現問題，請告訴我。 鑰匙0是一個開放空間1是牆壁2是路徑的一部分3是迷宮的末端
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();
}
}
}
2 個解決方案
解決方案1
5 2014-03-07 05:31:45
看到您已經接受了答案，但是無論如何我都會添加它...
遞歸可能是解決某些問題的一種非常優雅的方法，但要花點時間才能解決。 因此，這並不是您的代碼為何無法正常工作的確切答案，而更多的是在諸如此類的問題中使用遞歸的更高層次。
遞歸問題通常包含兩個部分：整體難題狀態和與當前嘗試相關的狀態。 整個遞歸過程都起作用，因為每次調用遞歸函數時，都會將一些新狀態推入調用堆棧，並且當函數退出時，它將為您刪除，因此您可以嘗試使用下一個選項。 您還可以在遞歸函數中操縱整體的拼圖狀態，但是通常在啟動時，我建議您對函數中的拼圖狀態所做的任何更改都應在退出時恢復。
因此，在您的情況下，迷宮本身是拼圖狀態，當前路徑是對整體拼圖狀態的臨時更改，而當前位置是與當前調用堆棧關聯的瞬態。
因此，整體解決方案開始采用以下形式：
// 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函數只是提供了起始坐標：
public static void main(String[] args) {
if (solve(1, 0)) {
print();
} else {
System.out.println("no solution found");
}
}
因此，下一步是“解決”功能的主體（我已將迷宮數據中的出口位置設置為3-請參閱最后的完整解決方案），其變為：
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;
}
首先檢查是否在出口處的簡單情況，如果是，則返回true。 如果沒有，我們將當前單元格推到路徑上，並尋找可用的鄰居。 如果找到一個，我們將依次嘗試每個，這是遞歸的核心...如果沒有可用的鄰居工作，則說明我們失敗了，必須回溯。
最后，如果要回溯，則必須從路徑中刪除當前單元格。
就是這樣。 “可用”功能僅檢查潛在單元格是否在邊界內，而不是在當前路徑上是否在牆壁上：
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);
}
完整代碼：
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決方案，而不僅僅是找到的第一個解決方案，則只需將已解決函數的頂部更改為：
// if we're at the goal then print it but return false to continue searching
if (maze[r][c] == 3) {
print();
return false;
}
快樂遞歸！
解決方案2
3 已采納 2014-03-07 03:56:25
在過去五個小時中，您已經問過有關此迷宮遞歸難題的四個問題，這證明它有多復雜。 這整個概念的1/0迷宮電網已吸引了我，我想出了一個類，應該讓一大堆簡單。 如果需要進行遞歸，那么它將對您沒有用，但是如果您可以使用它，那么它將消除很多復雜性。
有兩個類，一個枚舉。
首先，枚舉定義要在網格中移動的方向，並基於其移動一次確定新索引。
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;
}
};
主要類稱為MazePosition （下）。 首先，通過其int[][]構造函數在其中設置迷宮網格雙數組，並靜態存儲該實例：
private static final MazePosition MAZE_HOLDER = new MazePosition(MAZE_GRID);
（可以將這一步驟設計得更好，但是可以。）
設置迷宮網格（每次執行時，這是一次性的事情）后，然后使用x / y構造函數聲明初始位置：
MazePosition pos = new MazePosition(0, 0);
然后，根據需要移動：
pos = pos.getNeighbor(Direction.RIGHT);
pos = pos.getNeighbor(Direction.RIGHT);
pos = pos.getNeighbor(Direction.DOWN);
...
每個位置的值由pos.getValue()或pos.isPath()檢索-我認為1是“牆”， 0是“路徑”。 （順便說一句：巨大的2d數組實際上應該包含一個booleans ，而不是4字節的ints ，但是查看數組的代碼對int有意義，而對booleans則不行。請注意，它應該至少更改為byte s。）
因此，關於移動，如果您嘗試在沒有鄰居時獲得鄰居，例如在左邊緣向左移動，則會引發IllegalStateException 。 使用is*Edge()函數可以避免這種情況。
MazePosition類還有一個方便的調試函數，稱為getNineByNine() ，該函數返回9x9的數組值網格（作為字符串），其中中間項是當前位置。
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]);
}
}
它所沒有的是“碰撞檢測”或任何真正為您找到迷宮路徑的東西。 它只是在整個網格中移動，無論它是否穿過牆壁。 可以很容易地添加一些getNeighborIfNotWall(Direction)和isWallToLeft()函數，但我將留給您。 ;）
（實際上，這些類無需進行太多更改，就可以用於遍歷任何2D數組，盡管我可能會添加對角線方向（例如UP_LEFT ）以及移動多個步驟的能力，例如getNeighbor(3, Direction.DOWN) ）。
這是一個演示用法：
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());
}
}
輸出量
[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]
這是完整的源代碼文件，其中包含上述所有內容（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());
}
}
Java中的迷宮求解器問題
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