此刻再看优先队列，不像刚接触时的那般迷茫！这也许就是集训的成果吧！
加油！！！优先队列必须要搞定的！
这道题意很简单！自己定义优先级别！
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#include<stdio.h>
#include<string.h>
#include<queue>
using namespace std;
int n,m,dir[4][2]={1,0,0,1,-1,0,0,-1};
char s[1010][1010];
struct node
{
int x,y,step;
friend bool operator<(node a,node b)
{
return a.step>b.step;
}
/*
bool operator<(const node &b) const
{
return step>b.step;
}*/
};
bool judge(int x,int y)
{
if(x>=0&&x<n&&y>=0&&y<m&&s[x][y]!='#')
return true;
return false;
}
int bfs(int x0,int y0)
{
int k,x,y;
priority_queue<node>q;
node cur,next;
cur.x=x0;cur.y=y0;cur.step=0;
q.push(cur);
s[x0][y0]='#';
while(!q.empty())
{
cur=q.top();
q.pop();
for(k=0;k<4;k++)
{
x=next.x=cur.x+dir[k][0];
y=next.y=cur.y+dir[k][1];
next.step=cur.step+1;
if(judge(x,y))
{
if(s[x][y]=='r')
return next.step;
else if(s[x][y]=='.')
q.push(next);
else
{
next.step++;
q.push(next);
}
s[x][y]='#';
}
}
}
return -1;
}
int main()
{
int i,j,x,y,ans;
while(scanf("%d%d",&n,&m)!=EOF)
{
for(i=0;i<n;i++)
scanf("%s",s[i]);
for(i=0;i<n;i++)
{
for(j=0;j<m;j++)
if(s[i][j]=='a')
{
x=i;y=j;
}
if(j<m)
break;
}
ans=bfs(x,y);
if(ans==-1)
printf("Poor ANGEL has to stay in the * all his life.\n");
else
printf("%d\n",ans);
}
return 0;
}
题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=1242