///dabbysunshine@qq.com ///来源:《C语言程序设计（C99）》程良银.游洪跃等P266-269 ///迷宫问题的递归求解. ///============================================================================= #include <stdio.h> #include <stdlib.h> #define W 80 //迷宫宽的最大值 #define H 60 //迷宫高的最大值 /* 迷宫单元格状态: VIA:已经过;BLOCK:阻塞;EMPTY:空的. */ typedef enum {VIA,BLOCK,EMPTY} MazeCellStatus; typedef struct { int x,y; //单元格的坐标 } CellType; //迷宫单元格的类型 typedef struct { CellType path[W*H]; //经过路径 int length; //经过长度 } MazePathType; //迷宫路线类型 ///============================================================================= void outSolution(MazePathType mazePath); //输出迷宫问题的解 void trySolution(MazeCellStatus maze[][W],int w,int h,CellType exit, CellType cur,MazePathType mazePath);//试探求解下一位置 void mazeSolution(MazeCellStatus maze[][W],int w,int h, CellType entry,CellType exit); //迷宫问题 ///============================================================================= /**主函数部分**/ int main(void) { MazeCellStatus maze[H][W] = { {EMPTY,BLOCK,BLOCK,BLOCK,BLOCK,BLOCK,BLOCK,BLOCK,BLOCK,BLOCK}, {EMPTY,BLOCK,EMPTY,EMPTY,BLOCK,EMPTY,EMPTY,EMPTY,BLOCK,BLOCK}, {EMPTY,EMPTY,EMPTY,BLOCK,BLOCK,EMPTY,BLOCK,EMPTY,EMPTY,BLOCK}, {EMPTY,BLOCK,BLOCK,EMPTY,EMPTY,EMPTY,BLOCK,BLOCK,EMPTY,BLOCK}, {EMPTY,EMPTY,EMPTY,EMPTY,EMPTY,EMPTY,EMPTY,EMPTY,EMPTY,BLOCK}, {BLOCK,BLOCK,BLOCK,BLOCK,BLOCK,BLOCK,BLOCK,BLOCK,EMPTY,EMPTY}, }; CellType entry = {0,0}; /*入口位置*/ CellType exit = {9,5}; /*出口位置*/ int h = 6,w = 10; /*迷宫的高与宽*/ mazeSolution(maze,w,h,entry,exit); ///求解迷宫 return 0; } ///============================================================================= void mazeSolution(MazeCellStatus maze[][W],int w,int h, CellType entry,CellType exit) { MazePathType mazePath; mazePath.length = 0; /*迷宫路线初始长度为0*/ /*将入口存入路径，作为路径的起始点*/ mazePath.path[mazePath.length].x = entry.x; mazePath.path[mazePath.length].y = entry.y; mazePath.length ++; //路径长自增1 trySolution(maze,w,h,exit,entry,mazePath); ///用递归求解迷宫问题 } void trySolution(MazeCellStatus maze[][W],int w,int h,CellType exit, CellType cur,MazePathType mazePath) { int i; ///试探求解下一位置 int xShift[4] = {0,0,-1,1}; //相邻位置相对于当前位置的x坐标 int yShift[4] = {-1,1,0,0}; //相邻位置相对于当前位置的y坐标 CellType adjCell; //当前位置的相邻位置 if(cur.x == exit.x && cur.y == exit.y) { //已达到出口，输出解 outSolution(mazePath); } else { for(i = 0; i < 4; i ++) { adjCell.x = cur.x + xShift[i]; //求相邻位置的x坐标 adjCell.y = cur.y + yShift[i]; //求相邻位置的y坐标 if(adjCell.x >= 0 && adjCell.y >= 0 && adjCell.x < w && adjCell.y < h && (maze[adjCell.y][adjCell.x] == EMPTY)) { //相邻位置在迷宫内，并且为空白 //将相邻位置存入路径中 mazePath.path[mazePath.length].x = adjCell.x; mazePath.path[mazePath.length].y = adjCell.y; mazePath.length ++; //路径长自增1 maze[adjCell.y][adjCell.x] = VIA; //经过相邻位置 ///对相邻位置进行递归 trySolution(maze,w,h,exit,adjCell,mazePath); /*从路径中去掉adjCell，路径长度将自减1*/ mazePath.length –; /*恢复相邻位置为空白，回溯*/ maze[adjCell.y][adjCell.x] = EMPTY; } } } } void outSolution(MazePathType mazePath) { //输出迷宫的解 static int num = 0; int i; printf(“第%d条路径：/n”,++ num); //num为当前以求得解得个数 for(i = 0; i < mazePath.length; i ++) { printf(“(%d,%d)”,mazePath.path[i].x,mazePath.path[i].y); if((i + 1)%5 == 0) { printf(“/n”); } } printf(“/n/n”); }