Basic wall maze

In this problem you have to solve a very simple maze consisting of: 

1.a 6 by 6 grid of unit squares 
2.3 walls of length between 1 and 6 which are placed either horizontally or vertically to separate squares 
3.one start and one end marker 
A maze may look like this:



You have to find a shortest path between the square with the start marker and the square with the end marker. Only moves between adjacent grid squares are allowed; adjacent means that the grid squares share an edge and are not separated by a wall. It is not allowed to leave the grid.

1 6
2 6
0 0 1 0
1 5 1 6
1 5 3 5
0 0

NEEESWW

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <stack>

using namespace std;

const int MAX = 9,limit = 6,INF = 1000;
const int dirx[4]={0,-1,0,1},diry[4]={1,0,-1,0};

//map[x][y][0]-map[x][y][3] 分别表示坐标为x，y的格子的四个方向墙的情况，0为没墙，1为有墙
int map[MAX][MAX][4];
//pre[x][y][0]用来记录x，y的前驱格子的x坐标，pre[x][y][1]用来记录x，y的前驱格子的y坐标
int dist[MAX][MAX],pre[MAX][MAX][2];
int sx,sy,ex,ey,pax,pay,pbx,pby;
stack<char> st;

void init(){
	int i,j;

	for(i=0;i<MAX;++i){
		for(j=0;j<MAX;++j){
			dist[i][j] = INF;
			map[i][j][0] = map[i][j][1] = map[i][j][2] = map[i][j][3] = 0;
		}
	}
}

void dfs(int x,int y,int cnt){
	
	
	int i,tx,ty;

	for(i=0;i<4;++i){
		if(map[x][y][i]==1)continue;
		tx = x+dirx[i];
		ty = y+diry[i];
		if(tx<1 || ty<1 || tx>limit || ty>limit)continue;
		if(cnt+1>dist[tx][ty])continue;
		//更短就要更新，并且记录前驱
		dist[tx][ty] = cnt;
		pre[tx][ty][0] = x;
		pre[tx][ty][1] = y;
		dfs(tx,ty,cnt+1);
	}
}

void Path(){
	int px,py,x,y;

	x = ex,y = ey;
	px = pre[x][y][0];
	py = pre[x][y][1];

	while(1){
		//判断方向
		if(x==px){//x坐标相同看y坐标的情况
			if(py<y)st.push(‘E‘);
			else st.push(‘W‘);
		}else{//y坐标相同看x坐标的情况
			if(px<x)st.push(‘S‘);
			else st.push(‘N‘);
		}
		if(px==sx && py==sy)break;
		x = px;
		y = py;
		px = pre[x][y][0];
		py = pre[x][y][1];
	}

	while(!st.empty()){
		printf("%c",st.top());
		st.pop();
	}
	printf("\n");
}

int main(){
    //freopen("in.txt","r",stdin);
    //(author : CSDN iaccepted)
	int i,j;
	while(scanf("%d %d",&sy,&sx)){
		if(sx==0 && sy==0)break;
		scanf("%d %d",&ey,&ex);
		
		init();
		for(i=0;i<3;++i){
			scanf("%d %d %d %d",&pay,&pax,&pby,&pbx);
			if(pax==pbx){
				for(j=pay+1;j<=pby;++j){
					map[pax][j][3] = 1;
					map[pax+1][j][1] = 1;
				}
			}else{
				for(j=pax+1;j<=pbx;++j){
					map[j][pby][0] = 1;
					map[j][pby+1][2] = 1;
				}
			}
		}

		dfs(sx,sy,0);

		Path();
	}
		
    return 0;
}