c - C 语言中的回溯迷宫算法一开始就是错误的

Question

过去一周我们一直在致力于这个项目。除了初始化/分配和步骤函数之外的所有内容都是由我的教授预先提供给我的......

我们的目标不是创造迷宫，而是解决它。我第一次编译它时，它似乎运行良好，并且会稍微通过它...然后，它会开始做一些时髦的事情，跳过一堵墙，然后停在那里...

尝试修复并解决它。最终它没有迈出现在应该迈出的第一步。试图理解我做错了什么或者为什么我现在没有做正确的第一步在我的 maze_client...//已提供，但如果需要我可以更改一点

#include <stdio.h>
#include "maze.h"

int main(int argc, char **argv)
{
   FILE *fp = fopen(argv[1], "r");
   Maze maze = initializeMaze(fp);
   findPath(maze);// first step.. It was provided to me. It basically calls step() 
   displayMaze(maze);
   return 0;
}

Step 函数...我做了另一个不是 for 循环的函数，我试图看看是否也能摆脱这些废话。不起作用，只是让它在其他地方随机开始第一步...第二个文件完成了尝试，我屏蔽了每个函数...它似乎在我的 if(getBottom) 语句中。 .如果需要的话，我可以写下我想要它做什么的逻辑步骤......

static int step(Maze maze, int row, int column)
{
  //TODO: FINISH THE BACKTRACKING ALGORITHM
  int i,j;
  //int st;
  int successful;
 //maze->maze[row][column] = st;

 if(getVisit(maze, row, column) == maze->maze[maze->finishX][maze->finishY])
 {
   displayMaze(maze);
   return 1;
 }

 displayMaze(maze);
 getchar();
 // getVisit(maze, row, column);//gets pos
 for(i = -2; i <= 2; ++i)
 {
   for(j = -2; j <= 2; ++j)
   {
    //i*i != j*j dont move in diagonal
     //row+i >= 0 && row + i < n, bounds checking
     //col+j >= 0 && col+j < n, bounds checking
    if(i*i != j*j && row+i >= 0 && column+j >= 0 ) 
    {
      getVisit(maze, row, column);//Gets position 
        if(getCellHasTop(maze, row, column + 1) != 1)//Wall check, Zero meaning NO WALL
        {
                 //++st;
                 //gets that position and sees if it is unvisited... 
                 //need a test if it is visited.. if it has been visited before.. Set current spot as BAD_PATH
                 if(getVisit(maze,row,column+j) == UNVISITED)
                 {
                    setVisit(maze, row, column+1, GOOD_PATH);
                  successful = step(maze, row, column + 1);
                 }
              // if(getVisit(maze, row, column+j) == GOOD_PATH)
              //   {
              //   setVisit(maze, row-i, column, BAD_PATH);
          //   successful = step(maze, row, column+j);
            //      }
                 if(successful)
                   return 1;  
        }
        if(getCellHasLeft(maze,row - 1,column) != 1)
        {
                 if(getVisit(maze, row-1, column) == UNVISITED)
                 {
                 setVisit(maze, row-1, column, GOOD_PATH);
                 successful = step(maze, row-1, column);
                 }

              //   if(getVisit(maze, row-i, column) == GOOD_PATH)
               //  {
              //setVisit(maze, row-i, column, BAD_PATH);
              // successful = step(maze, row-i, column);
               //  }
                 //++st;
                 if(successful)
                return 1;
        }
        if(getCellHasRight(maze,row + 1, column) != 1)
        {
                 if(getVisit(maze, row+1, column) == UNVISITED)
                 {
                  setVisit(maze, row+1, column, GOOD_PATH);
                  successful = step(maze, row+1, column);
                 }

               //  if(getVisit(maze, row+i, column) == GOOD_PATH)
  //               {
    //            setVisit(maze, row+i, column, BAD_PATH);
      //            successful = step(maze, row+i, column);
        //        }
                 //++st;
                 if(successful)
                return 1;
        }
        if(getCellHasBottom(maze, row, column - 1) != 1)
        {
                 if(getVisit(maze, row, column-1) == UNVISITED)
                 {
                  setVisit(maze, row, column-1, GOOD_PATH);
                  successful = step(maze, row, column-1);
                 }

      //           if(getVisit(maze, row, column-j) == GOOD_PATH)
        //       {
          //        setVisit(maze, row, column-j, BAD_PATH);
            //    successful = step(maze, row, column-j);
              //   }
                 //++st;
                 if(successful)
                return 1;  
        }  
        //PART 2
        //Do not do else if because then each one would require... That is last resort
    if(getCellHasTop(maze, row, column + 1) == 0)//Wall check
        {
                 //++st;
                 //a test if it is visited.. if it has been visited before.. Set current spot as BAD_PATH   
                 if(getVisit(maze,row, column+1) == GOOD_PATH)
               {
                  setVisit(maze, row, column, BAD_PATH);
                  successful = step(maze, row, column + 1);
                }
                if(successful)
              return 1;  
        }
       if(getCellHasLeft(maze,row - 1,column) == 0)
        {
                 if(getVisit(maze, row-1, column) == GOOD_PATH)
                 {
               setVisit(maze, row, column, BAD_PATH);
                successful = step(maze, row-1, column);
                }
   //++st;
               if(successful)
            return 1;
 }
if(getCellHasRight(maze,row + 1, column) == 0)
        {
                if(getVisit(maze, row+1, column) == GOOD_PATH)
                {
                 setVisit(maze, row, column, BAD_PATH);
                 successful = step(maze, row+1, column);
                }
                 //++st;
      if(successful)
     return 1;
       }
       if(getCellHasBottom(maze, row, column - 1) == 0)
   {
                if(getVisit(maze, row, column-1) == GOOD_PATH)
 {
                  setVisit(maze, row, column, BAD_PATH);
                  successful = step(maze, row, column-1);
                }
                 //++st;
                 if(successful)
              return 1;  
       }  
        //Part 3
       if(getCellHasRight(maze, row + 1, column) != 0 && getCellHasLeft(maze,row - 1, column) != 0)// If there is a wall at those locationsZZ
        {
                if(getVisit(maze,row, column+1) == BAD_PATH)
                 {
                 setVisit(maze, row, column, BAD_PATH);
      successful = step(maze, row, column-1); 
                 }
                 if(successful)
                return 1;
 }
       if(getCellHasTop(maze, row, column + 1) != 0 && getCellHasBottom(maze, row, column - 1) != 0)
   {
                 if(getVisit(maze, row-1, column) == BAD_PATH)
                 {
                 setVisit(maze, row, column, BAD_PATH);
                  successful = step(maze, row+1, column);
                }
               if(successful)
              return 1;
     }
        if(getCellHasTop(maze, row, column +1) != 0 && getCellHasBottom(maze, row, column - 1) != 0)
      {
              if(getVisit(maze, row+1, column) == BAD_PATH)
           {
         setVisit(maze, row, column, BAD_PATH);
             successful = step(maze, row-1, column);
              }
         if(successful)
      return 1;
       }
      }  
     } 
     }
      displayMaze(maze);
      getchar();
    return 0;
    }

• 函数的完整代码:http://pastebin.com/PtAncpqS
• 头文件(已提供):http://pastebin.com/zYdCFMfX
• 扫描仪(已提供):http://pastebin.com/4nQdnXTP
• 扫描仪 header :http://pastebin.com/KjpFf83R
• 第二次尝试:http://pastebin.com/8qyuqtEv

Answer 1

我认为你的问题在于这样的代码:

    if(getCellHasTop(maze, row, column + 1) != 1)//Wall check, Zero meaning NO WALL
    {
             //++st;
             //gets that position and sees if it is unvisited... 
             //need a test if it is visited.. if it has been visited before.. Set current spot as BAD_PATH
             if(getVisit(maze,row,column+j) == UNVISITED)
             {
                setVisit(maze, row, column+1, GOOD_PATH);
              successful = step(maze, row, column + 1);
             }
          // if(getVisit(maze, row, column+j) == GOOD_PATH)
          //   {
          //   setVisit(maze, row-i, column, BAD_PATH);
      //   successful = step(maze, row, column+j);
        //      }
             if(successful)
               return 1;  
    }

首先，您从 -2 迭代到 +2。但我认为迷宫单元是连续的，所以你不应该这样做。相反，做这样的事情:首先，测试行、列以确保它们是迷宫中的有效位置。接下来，测试当前单元格的位，看看是否允许您向上或向任何方向移动。然后测试目标单元格是否有效。然后测试目标单元格是否被您已经经过的路径阻挡。然后跳进去。

enum {
    TOP_BLOCKED    = 0x01,
    RIGHT_BLOCKED  = 0x02,
    BOTTOM_BLOCKED = 0x04,
    LEFT_BLOCKED   = 0x08,
};

#define ABOVE(r,c)     (r),((c)+1)
#define BELOW(r,c)     (r),((c)-1)
#define LEFT_OF(r,c)   ((r)-1),(c)
#define RIGHT_OF(r,c)  ((r)+1),(c)

#define IN_MAZE(m,r,c) ((r)>=0 && (c)>=0 && (r)<(m)->rows && (c)<(m)->cols)
#define CELL(m,r,c) ((m)->maze[(r)][(c)])
#define TOP_OPEN(m,r,c) (in_maze(m, r, c) \
                        && !(CELL(m,r,c) & TOP_BLOCKED) 
                        && in_maze(m,ABOVE(r,c)))
#define VISITED(m,r,c) (getVisit(m,r,c) != UNVISITED)


// ... later, in your step function ...

#define POS  row,column

setVisit(maze, POS, GOOD_PATH);

if (TOP_OPEN(maze, POS) && !VISITED(maze, ABOVE(POS)) && step(maze, ABOVE(POS))) {
    // We found a successful path! Stop looking.
    return 1;
}

if (RIGHT_OPEN(maze, POS) ... && step(maze, RIGHT_OF(POS))) {
    return 1;
}

if (BOTTOM_OPEN ...

if (LEFT_OPEN ...
    return 1;
}

// There is no path from here that solves the maze.
setVisit(maze, POS, UNVISITED);
#undef POS

return 0;