HDU1180 诡异的楼梯 广搜 优先队列

5 5
**..T
**.*.
..|..
.*.*.
S....

7

Hint
Hint
 
地图如下：

#include<iostream>
#include<cstdio>
#include<cstring>
#include<queue>
#define qq  22
using namespace std;
char map[qq][qq];
int vis[qq][qq];
struct node
{
    int x,y,step;
     bool operator <(const node & t) const
    {
        return step>t.step;                     //模板 小的先出队列
    }
};
int fx1[5]= {0,0,1,-1};
int fx2[5]= {1,-1,0,0};
int m,n;
int sx,sy,ex,ey;
void bfs()
{
    priority_queue<node>q;  
    node now,next;
    now.x=sx;
    now.y=sy;
    now.step=0;
    q.push(now);
    vis[sx][sy]=1;
    while(!q.empty())
    {
        now=q.top();
        q.pop();
        if(map[now.x][now.y]=='T')
        {
            cout<<now.step<<endl;
            return;
        }
        for(int i=0; i<4; i++)
        {
            next.x=now.x+fx1[i];
            next.y=now.y+fx2[i];
            if(next.x<1||next.y<1||next.x>m||next.y>n||vis[next.x][next.y]==1)  
                continue;
            if(map[next.x][next.y]=='|')           //遇到楼梯
            {
                if(now.step%2==0&&(i==3||i==2))  
                {
                    next.x=next.x+fx1[i];
                    next.y=next.y+fx2[i];

                }
                else if(now.step%2==1&&(i==0||i==1))
                {
                    next.x=next.x+fx1[i];
                    next.y=next.y+fx2[i];
                }
                else                                    //不能经过楼梯时 
                    {
                        next.x=next.x+fx1[i];
                        next.y=next.y+fx2[i];
                          vis[next.x][next.y]=1;
                        next.step=now.step+2;     //step+2  这也就是用优先队列的原因
                        q.push(next);
                        continue;                 //不能和下面重复  一定要加
                    } 
            }
            if(map[next.x][next.y]=='-')
            {
                if(now.step%2==0&&(i==0||i==1))
                {
                    next.x=next.x+fx1[i];
                    next.y=next.y+fx2[i];
                }
                else if(now.step%2==1&&(i==3||i==2))
                {
                    next.x=next.x+fx1[i];
                    next.y=next.y+fx2[i];
                }
                else
                    {
                        next.x=next.x+fx1[i];
                        next.y=next.y+fx2[i];
                          vis[next.x][next.y]=1;
                        next.step=now.step+2;
                        q.push(next);
                        continue;
                    }
            }
            vis[next.x][next.y]=1;
            next.step=now.step+1;
            q.push(next);
        }
    }
    return;
}
int main()
{
    int i,j;
    while(~scanf("%d%d",&m,&n))
    {
        memset(vis,0,sizeof(vis));
        for(i=1; i<=m; i++)
            for(j=1; j<=n; j++)
            {
                cin>>map[i][j];
                if(map[i][j]=='*')                 //标记墙壁
                    vis[i][j]=1;
                if(map[i][j]=='S')                  //记录起点
                {
                    sx=i;
                    sy=j;
                }
            }
        bfs();
    }
    return 0;
}