hdu1242 Rescue BFS+优先队列

Rescue

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)

Total Submission(s): 29050    Accepted Submission(s): 10268

Problem Description

Angel was caught by the MOLIGPY! He was put in prison by Moligpy. The prison is described as a N * M (N, M <= 200) matrix. There are WALLs, ROADs, and GUARDs in the prison.

Angel's friends want to save Angel. Their task is: approach Angel. We assume that "approach Angel" is to get to the position where Angel stays. When there's a guard in the grid, we must kill him (or her?) to move into the grid. We assume that we moving up, down, right, left takes us 1 unit time, and killing a guard takes 1 unit time, too. And we are strong enough to kill all the guards.

You have to calculate the minimal time to approach Angel. (We can move only UP, DOWN, LEFT and RIGHT, to the neighbor grid within bound, of course.)

 

Input

First line contains two integers stand for N and M.

Then N lines follows, every line has M characters. "." stands for road, "a" stands for Angel, and "r" stands for each of Angel's friend.

Process to the end of the file.

 

Output

For each test case, your program should output a single integer, standing for the minimal time needed. If such a number does no exist, you should output a line containing "Poor ANGEL has to stay in the prison all his life."

 

Sample Input

7 8 #.#####. #.a#..r. #..#x... ..#..#.# #...##.. .#...... ........

 

Sample Output

13

思路：a是起点，r是终点，x多加一分钟，模板+简单模拟就行；

代码中不用visit也行，遍历后的点更新为#，就可以了；

#include
#include
#include
#include
using namespace std;
int visit[210][210];
char map[210][210];
int m,n;
struct node
{
	int x;
	int y;
	int step;
	bool friend operator<(node a,node b)
	{
		return a.step>b.step;
	}
};
void bfs(int startx,int starty,int endx,int endy)
{
	bool flag=false;
	priority_queue q;
	int move[4][2]={0,1,0,-1,1,0,-1,0};
	node now,next;
	now.x=startx;
	now.y=starty;
	now.step=0;
	q.push(now);
	while(!q.empty())
	{
		next=q.top();
		q.pop();
		if(next.x==endx && next.y==endy)
		{
			flag=true;
			break;
		}
		for(int i=0;i<4;i++)
		{
			now.x=next.x+move[i][0];
			now.y=next.y+move[i][1];
			if(map[now.x][now.y]!='#' && !visit[now.x][now.y] && now.x>=0 && now.x=0 && now.y