poj 2935 Basic Wall Maze bfs

/*
author:jxy
lang:C/C++
university:China,Xidian University
**If you need to reprint,please indicate the source**
*/
#include <cstdio>
#include <cstring>
#include <queue>
#define place(x,y) x+y*6
using namespace std;
const int dir[4][2]={0,-1,1,0,0,1,-1,0};
const char d[4]={'N','E','S','W'};
bool no[7][7][4];
int vis[40],start,end,now,next;
queue<int> q;
void output(int x)
{
if(x==start)return;
output(vis[x]/10);
printf("%c",d[vis[x]%10]);
}
int main()
{
int x,y,tx,ty,i;
while(scanf("%d%d",&x,&y)&&x+y)
{
memset(no,0,sizeof(no));
memset(vis,0,sizeof(vis));
while(!q.empty())q.pop();
start=place(--x,--y);
scanf("%d%d",&x,&y);
end=place(--x,--y);
for(i=0;i<3;i++)
{
scanf("%d%d%d%d",&x,&y,&tx,&ty);
if((x==tx&&(x==0||x==6))||(y==ty&&(y==0||y==6)))continue;
if(x==tx)
for(;y<ty;y++) no[x][y][3]=no[x-1][y][1]=1;
else
for(;x<tx;x++) no[x][y][0]=no[x][y-1][2]=1;
}
vis[start]=-1;
q.push(start);
while(!q.empty()&&!vis[end])
{
now=q.front();q.pop();
x=now%6;y=now/6;
for(i=0;i<4;i++)
{
tx=x+dir[i][0];
ty=y+dir[i][1];
next=place(tx,ty);
if(tx<0||tx>5||ty<0||ty>5||no[x][y][i]||vis[next])continue;
vis[next]=now*10+i;
q.push(next);
}
}
output(end);
puts("");
}
}