BFS

hdu 1180 诡异的楼梯

#include<cstdio>
#include <iostream>
using namespace std;
#include<algorithm>
#include <queue>
#include <cstring>
using namespace std;

const int N = 50;
const int INF = 1e6;
char Map[N][N];
bool vis[N][N];
int n,m;
int dir[4][2]={{1,0},{-1,0},{0,1},{0,-1}};

struct node{
    int x,y;
    int step;
    friend bool operator < (const node &a,const node &b)
    {
        return a.step>b.step;
    }
};
node st;
bool check(int x,int y)
{
    if(x>=0&&x<n&&y>=0&&y<m&&!vis[x][y]&&Map[x][y]!='*')
        return true;
    else
        return false;

}
int bfs(int x,int y)
{
    char c;
    priority_queue<node> q;
    node s_pos;
    s_pos.x = x;
    s_pos.y = y;
    s_pos.step  = 0;
    vis[s_pos.x][s_pos.y]=1;
    q.push(s_pos);
    while(!q.empty()){
        node tmp = q.top();
        q.pop();
        for(int i=0;i<4;i++)
        {
            node tmp2 ;
            tmp2 = tmp;
            tmp2.x += dir[i][0];
            tmp2.y += dir[i][1];
            tmp2.step += 1;
            if(check(tmp2.x,tmp2.y)&&(Map[tmp2.x][tmp2.y]=='-'||Map[tmp2.x][tmp2.y]=='|')){
                if(tmp2.step % 2 == 1){
                    if(Map[tmp2.x][tmp2.y] == '-') c = '|';
                    else if(Map[tmp2.x][tmp2.y]=='|') c = '-';
                }else c = Map[tmp2.x][tmp2.y];
                tmp2.x += dir[i][0];
                tmp2.y += dir[i][1];
                if((c =='-'&&(dir[i][1]==-1||dir[i][1]==1))||(c =='|'&&(dir[i][0]==-1||dir[i][0]==1)))
                    tmp2.step += 1;//判断是否需要时间来等待楼梯
            }
            if(check(tmp2.x,tmp2.y)){
                if(Map[tmp2.x][tmp2.y]=='T') return tmp2.step;
                vis[tmp2.x][tmp2.y] = 1;
                q.push(tmp2);
            }
        }
    }
}
int main()
{
    while(cin>>n>>m)
    {
        for(int i=0;i<n;i++)
        {
            for(int j=0;j<m;j++)
            {
                cin>>Map[i][j];
                if(Map[i][j]=='S'){
                    st.x=i;
                    st.y=j;
                }
            }
        }
        memset(vis,0,sizeof(vis));
        int ans = bfs(st.x,st.y);
        printf("%d
",ans);
    }
   return 0;
}