hdu 3309 Roll The Cube ( bfs )
Roll The Cube
Time Limit: 3000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 345 Accepted Submission(s): 127
Problem Description
This is a simple game.The goal of the game is to roll two balls to two holes each.
'B' -- ball
'H' -- hole
'.' -- land
'*' -- wall
Remember when a ball rolls into a hole, they(the ball and the hole) disappeared, that is , 'H' + 'B' = '.'.
Now you are controlling two balls at the same time.Up, down , left , right --- once one of these keys is pressed, balls exist roll to that direction, for example , you pressed up , two balls both roll up.
A ball will stay where it is if its next point is a wall, and balls can't be overlap.
Your code should give the minimun times you press the keys to achieve the goal.
'B' -- ball
'H' -- hole
'.' -- land
'*' -- wall
Remember when a ball rolls into a hole, they(the ball and the hole) disappeared, that is , 'H' + 'B' = '.'.
Now you are controlling two balls at the same time.Up, down , left , right --- once one of these keys is pressed, balls exist roll to that direction, for example , you pressed up , two balls both roll up.
A ball will stay where it is if its next point is a wall, and balls can't be overlap.
Your code should give the minimun times you press the keys to achieve the goal.
Input
First there's an integer T(T<=100) indicating the case number.
Then T blocks , each block has two integers n , m (n , m <= 22) indicating size of the map.
Then n lines each with m characters.
There'll always be two balls(B) and two holes(H) in a map.
The boundary of the map is always walls(*).
Then T blocks , each block has two integers n , m (n , m <= 22) indicating size of the map.
Then n lines each with m characters.
There'll always be two balls(B) and two holes(H) in a map.
The boundary of the map is always walls(*).
Output
The minimum times you press to achieve the goal.
Tell me "Sorry , sir , my poor program fails to get an answer." if you can never achieve the goal.
Tell me "Sorry , sir , my poor program fails to get an answer." if you can never achieve the goal.
Sample Input
4
6 3
***
*B*
*B*
*H*
*H*
***
4 4
****
*BB*
*HH*
****
4 4
****
*BH*
*HB*
****
5 6
******
*.BB**
*.H*H*
*..*.*
******
Sample Output
3
1
2
Sorry , sir , my poor program fails to get an answer.
Author
MadFroG
Source
思路:
bfs,用两个球的位置来判重,其他的直接模拟就ok了。最好将球和洞分开看,还有就是注意一下两个球不能在同一个位置。
代码:
#include <iostream> #include <cstdio> #include <cstring> #include <queue> #define maxn 25 #define INF 0x3f3f3f3f using namespace std; int n,m,ans; int sx[2],sy[2]; int dx[]= {-1,1,0,0}; int dy[]= {0,0,-1,1}; bool vis[maxn][maxn][maxn][maxn]; char mp[maxn][maxn]; char s[maxn]; struct Node { int x[2],y[2],step; int b[2],h[2]; // 球 洞 球是否进洞和洞是否被求填满分开看 } cur,now; queue<Node>q; bool bfs() { int i,j,t,flag; memset(vis,0,sizeof(vis)); while(!q.empty()) q.pop(); cur.x[0]=sx[0],cur.y[0]=sy[0]; cur.x[1]=sx[1],cur.y[1]=sy[1]; cur.h[0]=cur.h[1]=0; cur.b[0]=cur.b[1]=0; cur.step=0; vis[sx[0]][s[0]][sx[1]][sy[1]]=1; q.push(cur); while(!q.empty()) { now=q.front(); q.pop(); for(i=0; i<4; i++) { cur=now; for(j=0; j<2; j++) { if(cur.b[j]) continue ; cur.x[j]+=dx[i]; cur.y[j]+=dy[i]; if(mp[cur.x[j]][cur.y[j]]=='*') { cur.x[j]-=dx[i]; cur.y[j]-=dy[i]; } } if(vis[cur.x[0]][cur.y[0]][cur.x[1]][cur.y[1]]||cur.x[0]==cur.x[1]&&cur.y[0]==cur.y[1]&&cur.b[0]+cur.b[1]==0) continue ; cur.step++; vis[cur.x[0]][cur.y[0]][cur.x[1]][cur.y[1]]=1; flag=1; for(j=0; j<2; j++) { t=mp[cur.x[j]][cur.y[j]]; if(t<2&&!cur.h[t]) cur.b[j]=1,cur.h[t]=1; if(!cur.b[j]) flag=0; } if(flag) { ans=cur.step; return true ; } q.push(cur); } } return false ; } int main() { int i,j,t,cnt1,cnt2; scanf("%d",&t); while(t--) { scanf("%d%d",&n,&m); cnt1=cnt2=0; for(i=1; i<=n; i++) { scanf("%s",s); for(j=1; j<=m; j++) { mp[i][j]=s[j-1]; if(mp[i][j]=='H') mp[i][j]=cnt1++; else if(mp[i][j]=='B') sx[cnt2]=i,sy[cnt2]=j,cnt2++; } } if(bfs()) printf("%d\n",ans); else printf("Sorry , sir , my poor program fails to get an answer.\n"); } return 0; }