迷宫寻路

#include<stdio.h>
#include<stdlib.h>
#define MAXSIZE 50
#define ERROR -1
#define OK 0
#define FALSE 0
#define TRUE 1
typedef enum{RIGHT,DOWN,LEFT,UP}Direction;
typedef enum{YES,NO}MarkTag;
typedef struct position{
    int x;int y;
}Position;
typedef struct{
    int order;
    Position seat;
    Direction di;
}SElemType;
typedef struct{
    SElemType *elem;
    int top;
}Stack;
char maze[MAXSIZE+2][MAXSIZE+2];
int InitStack(Stack *S)
{
    S->elem=(SElemType*)malloc(MAXSIZE*MAXSIZE*sizeof(SElemType));
    if(!S->elem) return ERROR;
    S->top=0;return OK;
}
int Push(Stack *S,SElemType e)
{
    if(S->top>=MAXSIZE*MAXSIZE) return ERROR;
    S->elem[S->top++]=e;
    return OK;
}
int Pop(Stack *S,SElemType *e)
{
    if(S->top<=0) return ERROR;
    *e=S->elem[--S->top];return OK;
}
int Empty(Stack S)
{
    if(S.top==0) return TRUE;
    return FALSE;
}

int CreateMaze(char *filename,Position *startpos,Position *endpos)
{
    FILE *fp;
    int i,j,rows,cols,temp;
    Position start,end;
    fp=fopen(filename,"r");
    if(!fp)
    {printf("open file %s error!\n",filename);
    return ERROR;
    }
    if(!feof(fp))
    {
        fscanf(fp,"%d %d",&rows,&cols);
        fscanf(fp,"%d %d",&start.x,&start.y);
        fscanf(fp,"%d %d",&end.x,&end.y);
    }
    for(i=1;i<=rows;i++)
        for(j=1;j<=cols;j++)
        {
            fscanf(fp,"%d",&temp);
            maze[i][j]=48+temp;
        }
        fclose(fp);
        for(i=0,j=0;i<rows+1;i++) maze[i][j]='1';
        for(i=0,j=cols+1;i<rows+1;i++) maze[i][j]='1';
        for(i=0,j=0;j<cols+1;j++) maze[i][j]='1';
        for(i=rows+1,j=0;j<cols+1;j++) maze[i][j]='1';
        *startpos=start;*endpos=end;
        return OK;
}

int canPass(Position curpos)
{
    if(maze[curpos.x][curpos.y]=='0') return TRUE;
    return FALSE;
}

void markPos(Position curpos,MarkTag tag)
{
    switch(tag)
    {
    case YES:maze[curpos.x][curpos.y]='.';break;
    case NO:maze[curpos.y ][curpos.y ]='#';break;
    }
}

Position nextPos(Position curpos,Direction dir)
{
    Position nextpos;
    switch(dir)
    {
    case RIGHT:nextpos.x=curpos.x;nextpos.y =curpos.y+1;break;
    case DOWN:nextpos.x =curpos.x +1;nextpos.y =curpos.y;break;
    case LEFT:nextpos.x=curpos.x;nextpos.y =curpos.y-1;break;
    case UP:nextpos.x=curpos.x-1;nextpos.y =curpos.y;break;
    }
    return nextpos;
}

Direction nextDir(Direction dir)
{
    switch(dir)
    {
    case RIGHT:return DOWN;
    case DOWN:return LEFT;
    case LEFT:return UP;
    }
}

int Solve(Stack *S,Position start,Position end)
{
    Position curpos;
    SElemType e;
    int curstep=1;
    if(InitStack(S)==ERROR) return FALSE;
    curpos=start;
    do{
        if(canPass(curpos))
        {
            markPos(curpos,YES);
            e.order=curstep;e.seat=curpos;e.di=RIGHT;
            Push(S,e);
            if(curpos.x==end.x &&curpos.y ==end.y)
                return TRUE;
            curpos=nextPos(curpos,RIGHT);
            curstep++;
        }
        else
        {
            if(!Empty(*S))
            {
                if(Pop(S,&e)==ERROR) return FALSE;
                while(e.di ==UP&&!Empty(*S))
                {
                    curpos=e.seat;markPos(curpos,NO);
                    if(Pop(S,&e)==ERROR) return FALSE;
                }
                if(e.di!=UP)
                {
                    e.di=nextDir(e.di);
                    Push(S,e);
                    curpos=nextPos(e.seat,e.di);
                }
            }
        }
    }while(!Empty(*S));
    return FALSE;
}

void main(void)
{
    Position startPos,endPos;
    Stack path;
    SElemType e;
    char *fname="in.txt";
    if(CreateMaze(fname,&startPos,&endPos)==ERROR) return;
    Solve(&path,startPos,endPos);
    while(!Empty(path))
    {
        Pop(&path,&e);
        printf("(%d,%d)\n",e.seat.x,e.seat.y);
    }
}