Rescue

杭电1242

Sample Input

7 8

#.#####.

#.a#..r.

#..#x...

..#..#.#

#...##..

.#......

........

 

Sample Output

13

//杭电1242
#include<stdio.h>
#include<queue>
using namespace std;
#define N 202
char map[N][N];
int mark[N][N];
int m,n,x,y,flag;
int d[4][2]={1,0,-1,0,0,1,0,-1};
typedef struct
{
    int x;
    int y;
    int step;
}point;
void dfs()
{
    queue<point>q;
    point p,c,t;
    int i;
    p.x=x;
    p.y=y;
    p.step=0;
    mark[x][y]=1;//标记起始点以走过，防止重复

    flag=0;
    q.push(p);
    while(!q.empty())
    {
        c=q.front();//取队头元素

        q.pop();//队头元素出队

        if(map[c.x][c.y]=='x')//如果遇到卫兵,则时间加1,入队该点,并将该点变成可行路径
        {
            c.step++;
            map[c.x][c.y]='.';
            q.push(c);
        }
        else
        {
            for(i=0;i<4;i++) //扫描四周,寻找路径

            {
                t.x=c.x+d[i][0];
                t.y=c.y+d[i][1];
                t.step=c.step+1;
                if(map[t.x][t.y]!='#'&&mark[t.x][t.y]==0&&t.x>=0&&t.y>=0&&t.x<m&&t.y<n)
                {
                    if(map[t.x][t.y]=='a') //如果找到则输出
                    {
                        printf("%d\n",t.step);
                            flag=1;
                        return;
                    } 
                    //没找到则入队该点继续寻找

                    mark[t.x][t.y]=1;
                    q.push(t);
                }
            }
        }
    }
    if(flag==0)
        printf("Poor ANGEL has to stay in the prison all his life.\n");
}


int main()
{
    int i,j;
    while(scanf("%d%d",&m,&n)!=-1)
    {
        for(i=0;i<m;i++)
            scanf("%s",map[i]);
        for(i=0;i<m;i++)
        {
            for(j=0;j<n;j++)
            {
                if(map[i][j]=='r')//标记初始点
                {
                    x=i;
                    y=j;
                }
                mark[i][j]=0;//初始化标记数组
            }
        }
        dfs();
    }
    return 0;
}