迷宫问题---poj3984（bfs，输出路径问题）

#include<stdio.h>
#include<iostream>
#include<string.h>
#include<queue>
#include<algorithm>
using namespace std;
#define N 220
#define INF 0xfffffff

int dir[4][2] = { {1,0},{-1,0},{0,1},{0,-1} };
int map

;
int vis

, n, m;
struct node
{
int x, y, step;
friend bool operator<(node a, node b)
{
return a.step>b.step;
}
}pre

,path
;

node bfs()
{
memset(vis, 0,sizeof(vis));
vis[0][0] = 1;
priority_queue<node> Q;
node p,q;
p.x = p.y = p.step = 0;
Q.push(p);
while(Q.size())
{
p=Q.top(); Q.pop();
if(p.x == 4 && p.y == 4)
return p;
for(int i=0; i<4; i++)
{
q.x=p.x+dir[i][0];
q.y=p.y+dir[i][1];
if(q.x>=0&&q.x<5 && q.y>=0&&q.y<5 && map[q.x][q.y]==0 && vis[q.x][q.y]==0)
{
vis[q.x][q.y] = 1;
q.step = p.step + 1;
pre[q.x][q.y].x = p.x;
pre[q.x][q.y].y = p.y;
Q.push(q);
}
}
}
}

int main()
{
for(int i=0; i<5; i++)
{
for(int j=0; j<5; j++)
scanf("%d",&map[i][j]);
}
node ans = bfs();
int step = ans.step, x = ans.x, y = ans.y;
for(int i=step-1; i>=0; i--)
{
path[i].x = pre[x][y].x;
path[i].y = pre[x][y].y;
x = path[i].x;
y = path[i].y;
}
for(int i=0;i<step;i++)
{
printf("(%d, %d)\n",path[i].x, path[i].y);
}
printf("(4, 4)\n");
return 0;
}