hdu 1429

http://acm.hdu.edu.cn/showproblem.php?pid=1429

一个广搜的简单题吧，不过有意思的事这个题目用到了位运算，还有就是很恶心的MLE

 #include <stdio.h>
 #include <string.h>
 #include <queue>
 using namespace std;

 int m,n,t;
 char graph[][];
 bool vis[][][<<];
 int dic[][] = {-,,,,,-,,};
 struct note{

     int x,y,state,time;

 }loc;
 queue<note>s;
 /*
     位运算就是在下面，对于每一个钥匙用二进制的0,1来存
 */
 int bfs(int x,int y)
 {
     while(!s.empty())
         s.pop();
     loc.state = ;
     loc.time = ;
     loc.x = x;
     loc.y = y;
     s.push(loc);
     while(!s.empty())
     {
         note fa,son;
         fa = s.front();
         s.pop();
       //  if(fa.time == t) return -1;
         for(int i =  ; i <  ; i++)
         {
             son.x = fa.x + dic[ i ][  ];
             son.y = fa.y + dic[ i ][  ];
             if(son.x <  || son.y < || son.y > n || son.x > m||!vis[son.x][son.y][fa.state]) continue;     //这一行很关键，没有这一行就是MLE
             if(graph[son.x][son.y] == '^')
             {
                 if(fa.time == t ) return -;
                 else return fa.time;
             }
             if(graph[son.x][son.y] >='a'&& graph[son.x][son.y] <='z' &&vis[son.x][son.y][fa.state| ( <<(graph[son.x][son.y]-'a'))])
             {
                 son.state = fa.state | ( <<(graph[son.x][son.y]-'a'));
                 son.time = fa.time+;
                 vis[son.x][son.y][son.state] = false;
                 s.push(son);
             }
             else if(graph[son.x][son.y]<='Z' && graph[son.x][son.y] >='A' && fa.state & ( << graph[son.x][son.y]-'A') &&vis[son.x][son.y][fa.state])
             {
                 son.state = fa.state;
                 son.time = fa.time+;
                 vis[son.x][son.y][son.state] = false;
                 s.push(son);
             }
            else if(graph[son.x][son.y]=='.'||graph[son.x][son.y]=='@'&&vis[son.x][son.y][fa.state])
             {
                 son.state = fa.state;
                 son.time = fa.time +  ;
                 vis[son.x][son.y][son.state] = false;
                 s.push(son);
             }
         }
     }
     return -;
 }

 int main()
 {
  //   freopen("in.txt","r",stdin);
     int x,y;
     while(~scanf("%d%d%d",&m,&n,&t))
     {
         getchar();        //吃掉一个换行符
         memset(graph,,sizeof(graph));
         memset(vis,true,sizeof(vis));
         int ans;
         for(int i =  ; i <= m; i++)
         {
             for(int j =  ; j <= n ; j++)
             {
                 scanf("%c",&graph[i][j]);
                 if(graph[i][j]=='@')
                     x = i,y = j;
             }
             getchar();
         }
         ans = bfs(x,y);
         printf("%d\n",ans);
     }
     return ;
 }