CodeForces 676D代码 哪里有问题呢？

题目：

http://codeforces.com/problemset/problem/676/D

code:

#include <stdio.h>
#define MAXN 1001
#define LEFT 0
#define TOP 1
#define RIGHT 2
#define BOTTOM 3
struct block{
    //left,top,right,bottom
    int doors[4];
    int doors_num;
    int rotats;
    int minutes;
};
struct block labyrinth[MAXN][MAXN];
char visited[MAXN][MAXN];

struct node{
    int x;
    int y;
};
int top;
struct node path[MAXN*MAXN];
int N,M;
int xt,yt,xm,ym;
int min_minutes = 0x0FFFFFFF;
void init_doors(int x,int y,char c)
{
    int i;
    for (i=0;i<4;i++)
    {
        labyrinth[x][y].doors[i] = 0;
    }
    labyrinth[x][y].doors_num =0;
    labyrinth[x][y].rotats = 0;
    labyrinth[x][y].minutes = 0x0FFFFFFF;
    switch(c)
    {
    case '+':
        for (i=0;i<4;i++)
        {
            labyrinth[x][y].doors[i] = 1;
        }
        labyrinth[x][y].doors_num = 4;
        labyrinth[x][y].rotats = 0;
        break;
    case '-':
        labyrinth[x][y].doors[LEFT] = 1;
        labyrinth[x][y].doors[RIGHT] =1;
        labyrinth[x][y].doors_num = 2;
        break;
    case '|':
        labyrinth[x][y].doors[TOP] = 1;
        labyrinth[x][y].doors[BOTTOM] =1;
        labyrinth[x][y].doors_num = 2;
        break;
    case '^':
        labyrinth[x][y].doors[TOP] = 1;
        labyrinth[x][y].doors_num = 1;
        break;
    case '>':
        labyrinth[x][y].doors[RIGHT] = 1;
        labyrinth[x][y].doors_num = 1;
        break;
    case '<':
        labyrinth[x][y].doors[LEFT] = 1;
        labyrinth[x][y].doors_num = 1;
        break;
    case 'V':
        labyrinth[x][y].doors[BOTTOM] = 1;
        labyrinth[x][y].doors_num = 1;
        labyrinth[x][y].rotats = 0;
        break;
    case 'L':
        labyrinth[x][y].doors[TOP] = 1;
        labyrinth[x][y].doors[BOTTOM] =1;
        labyrinth[x][y].doors[RIGHT] = 1;
        labyrinth[x][y].doors_num =3;
        labyrinth[x][y].rotats = 0;
        break;
    case 'R':
        labyrinth[x][y].doors[TOP] = 1;
        labyrinth[x][y].doors[BOTTOM] =1;
        labyrinth[x][y].doors[LEFT] = 1;
        labyrinth[x][y].doors_num = 3;
        labyrinth[x][y].rotats = 0;
        break;
    case 'U':
        labyrinth[x][y].doors[RIGHT] = 1;
        labyrinth[x][y].doors[BOTTOM] =1;
        labyrinth[x][y].doors[LEFT] = 1;
        labyrinth[x][y].doors_num = 3;
        break;
    case 'D':
        labyrinth[x][y].doors[TOP] = 1;
        labyrinth[x][y].doors[RIGHT] =1;
        labyrinth[x][y].doors[LEFT] = 1;
        labyrinth[x][y].doors_num = 3;
        break;
    }
}
void push(int i,int j)
{
    top++;
    path[top].x = i;
    path[top].y = j;
    
}
struct node pop()
{
    top--;
    return path[top +1];
}
int get_door(int x,int y,int direction,int roates)
{
    int t = roates % 4;
    int index = direction - t;
    if (index < 0)
    {
        index += 4;
    }

    return labyrinth[x][y].doors[index];

}
void process_state(int x,int y,int cur_rotates,int cur_time)
{
    int dir_y[4] = {-1,0,1,0};
    int dir_x[4] = { 0,-1,0,1};
    int i,nx,ny;
    for (i=0;i<4;i++)
    {
        nx = x+dir_x[i];
        ny = y+dir_y[i];
        if (nx<1 || nx >N)
        {
            continue;
        }
        if (ny<1 || ny>M)
        {
            continue;
        }
        if (get_door(x,y,i,cur_rotates)&& get_door(nx,ny,(i+2)%4,cur_rotates))
        {
            if (!visited[nx][ny])
            {
                visited[nx][ny] =1;
                labyrinth[nx][ny].minutes = cur_time+1;
                labyrinth[nx][ny].rotats = cur_rotates;
                if (nx == xm && ny == ym)
                {
                    if (min_minutes > cur_time+1)
                    {
                        min_minutes = cur_time+1;
                    }
                }else
                {

                    push(nx,ny);
                }

            }else
            {
                if (labyrinth[nx][ny].minutes >cur_time+1 )
                {
                    labyrinth[nx][ny].minutes = cur_time+1;
                    labyrinth[nx][ny].rotats = cur_rotates;
                    push(nx,ny);
                }
            }
        }

    }
}
int bfs()
{
    int x,y,cur_rotates,i,nx,ny,t,cur_time;
    
    struct node cur;
    top = -1;
    push(xt,yt);
    labyrinth[xt][yt].minutes = 0;
    visited[xt][yt] =1;
    
    while(top!= -1)
    {
        cur = pop();

        //left
        x = cur.x;
        y = cur.y;
        cur_rotates = labyrinth[x][y].rotats;
        cur_time = labyrinth[x][y].minutes;
        t = 0;
        while(t < 4)
        {
            if (cur_time + t < min_minutes)
            {
                process_state(x,y,cur_rotates+t,cur_time+t);
            }
            t++;
            
        }
    }
    return labyrinth[xm][ym].minutes;
        
}
int main()
{
    int i,j;
    char str[MAXN];
    scanf("%d %d",&N,&M);
    for (i=1;i<=N;i++)
    {
        scanf("%s ",str);
        for (j=1;j<=M;j++)
        {
            
            init_doors(i,j,str[j-1]);
            visited[i][j] = 0;
        }
    }
    scanf("%d %d",&xt,&yt);
    scanf("%d %d",&xm,&ym);
    //check same logcation
    if (xt == xm && yt == ym)
    {
        printf("0");
        return 0;
    }
    //dfs(xt,yt,0);
    
    bfs();
    if(min_minutes == 0x0FFFFFFF)
        printf("-1");
    else
        printf("%d",min_minutes);


    return 0;
}