ZOJ 2594 Driving Straight（最短路）

题意：求左下角到右上角的最短路，按照方向输出　　

解题思路:优先方向的广搜，格式错误判WA

解题代码：

// File Name: 2594.c
// Author: darkdream
// Created Time: 2013年09月07日 星期六 22时18分29秒

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<time.h>
#include<math.h>
#define LL long long
int map[1000][1000];
int visit[1000][1000];
char str[1000][1000];
//freopen("/home/plac/problem/input.txt","r",stdin);
//freopen("/home/plac/problem/output.txt","w",stdout);
int xadd[] = {0,0,1,-1,0,0,1,-1};
int yadd[] = {1,-1,0,0,1,-1,0,0};
int n, m;
struct node{
    int  x , y ,k,last;
}list[1000*1000];
struct node1
{
    int x, y ;
}step[1000*1000];
int is(int x,int y)
{
    if(str[x][y] == '+')
        return 1; 
    return 0 ;
}
int main(){
    int t ;
    scanf("%d",&t);
    while(t--)
    {
        scanf("%d %d\n",&n,&m);
        n = n*2-1;
        m = m*2-1;
        memset(map,0,sizeof(map));
        memset(visit,0,sizeof(visit));
        memset(step,0,sizeof(step));
        memset(list,0,sizeof(list));
        memset(str,0,sizeof(str));
        for(int i =1;i<= n;i ++)
        {
            gets(&str[i][1]);
            for(int j = 1;j <= m;j ++)
            {
                if(str[i][j] == '+' || str[i][j] == '|' || str[i][j] == '-')
                    map[i][j] = 1; 
            }
        }
        list[1].x = n; 
        list[1].y = 1;
        list[1].last = 0 ; 
        list[1].k = 0 ; 
        int low = 1,high = 1 ;
        /*for(int i =1;i <= n;i ++)
          {
          for(int j = 1; j<=m;j++)
          printf("%d ",map[i][j]);
          printf("\n");
          }*/
        while(low <= high)
        {
            if(list[low].x == 1 && list[low].y == m)
            {
                break;
            }
                for(int i = list[low].k ;i <= list[low].k+3; i++)
                {
                    int tx = list[low].x + xadd[i];
                    int ty = list[low].y + yadd[i];
                    if(map[tx][ty] && !visit[tx][ty])
                    {
                        visit[tx][ty] = 1; 
                        high ++;
                        list[high].x = tx;
                        list[high].y = ty;
                        list[high].last = low;
                        list[high].k = i % 4;  
                    }
                }
            low++;
        }
        int k = 0;
        while(list[low].last)
        {
            k++;
            step[k].x = list[low].x;
            step[k].y = list[low].y;
            low = list[low].last;
        }
        /*    for(int i = k ;i >= 1; i --)
            {
            printf("%d %d\n",step[i].x,step[i].y);
            } */
        int ld,d;
        if(step[k].x == n-1)
        {
            printf("N\n");
            ld = 1; 
        }else{
            printf("E\n");
            ld = 2;
        }
        for(int i = k-1 ;i >= 1;i --){
            if(ld == 1)
            {
                if(step[i].x - step[i+1].x == -1)
                {
                    d = 1;
                    if(is(step[i+1].x,step[i+1].y))
                        printf("F");
                }else if(step[i].y - step[i+1].y == 1){
                        printf("R");
                    d = 2; 
                }else {
                        printf("L");
                    d = 4;
                }
            }
            else if(ld == 2){
                if(step[i].y - step[i+1].y == 1)
                {
                    d = 2;
                    if(is(step[i+1].x,step[i+1].y))
                        printf("F");
                }else if(step[i].x - step[i+1].x == 1){
                        printf("R");
                    d = 3; 
                }else {
                        printf("L");
                    d = 1;
                }

            }else if(ld == 3){
                if(step[i].x - step[i+1].x == 1)
                {
                    d = 3;
                    if(is(step[i+1].x,step[i+1].y))
                        printf("F");
                }else if(step[i].y - step[i+1].y == 1){
                        printf("L");
                    d = 2; 
                }else {
                        printf("R");
                    d = 4;
                }


            }else {
                if(step[i].y - step[i+1].y == -1)
                {
                    d = 4;
                    if(is(step[i+1].x,step[i+1].y))
                        printf("F");
                }else if(step[i].x - step[i+1].x == 1){
                        printf("L");
                    d = 3; 
                }else {
                        printf("R");
                    d = 1;
                }


            }
            ld = d;    
        }
        printf("\n");
        if(t != 0 )
            printf("\n");
    }
    return 0 ;
}