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): 680    Accepted Submission(s): 272

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.

 

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(*).

 

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.

 

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.

BFS 要注意一个球进了洞，那么这个球和洞都消失了，变成了.
只剩另一个球了。
#include <iostream>
#include <string.h>
#include <stdlib.h>
#include <algorithm>
#include <stdio.h>
#include <math.h>
#include <queue>

using namespace std;
char a[105][105];
int dp[25][25][25][25];
int dir[4][2]={{1,0},{-1,0},{0,1},{0,-1}};
int n,m;
struct Node
{
    int x1,y1,x2,y2;
    int time;
    int tag1;
    int tag2;
    int X1,Y1,X2,Y2;
    Node(){};
    Node(int x1,int y1,int x2,int y2,int time,int tag1,int tag2)
    {
        this->x1=x1;
        this->y1=y1;
        this->x2=x2;
        this->y2=y2;
        this->time=time;
        this->tag1=tag1;
        this->tag2=tag2;
    }
};
queue<Node> q;
int BFS(int x1,int y1,int x2,int y2)
{

    q.push(Node(x1,y1,x2,y2,0,0,0));
    Node term;
    dp[x1][y1][x2][y2]=1;
    int xx1,yy1,xx2,yy2;
    int xo1,yo1,xo2,yo2;
    while(!q.empty())
    {
        term=q.front();
        q.pop();
        if(a[term.x1][term.y1]=='H')
        {
            if(term.tag2==0)
                term.tag1=1;
            if(term.tag2)
            {
                if(term.x1!=term.x2)
                    term.tag1=1;
                if(term.y1!=term.y2)
                    term.tag1=1;
            }

        }
        if(a[term.x2][term.y2]=='H')
        {
            if(term.tag1==0)
                term.tag2=1;
            if(term.tag1)
            {
                if(term.x1!=term.x2)
                    term.tag2=1;
                if(term.y1!=term.y2)
                    term.tag2=1;
            }
        }
        if(term.tag1&&term.tag2)
        {
            return term.time;
        }
        for(int i=0;i<4;i++)
        {
            xo1=xx1=term.x1+dir[i][0];
            xo2=xx2=term.x2+dir[i][0];
            yo1=yy1=term.y1+dir[i][1];
            yo2=yy2=term.y2+dir[i][1];
            if(term.tag1!=0)
            {
                xo1=xx1=term.x1;
                yo1=yy1=term.y1;
            }
            if(term.tag2!=0)
            {
                xo2=xx2=term.x2;
                yo2=yy2=term.y2;
            }
            if(!term.tag1)
            {
                if(a[xx1][yy1]=='*') {xx1=term.x1;yy1=term.y1;}
                else if(xx1==term.x2&&yy1==term.y2)
                {
                    if(a[xo2][yo2]=='*')
                    {xx1=term.x1;yy1=term.y1;}
                }
            }
            if(!term.tag2)
            {
                if(a[xx2][yy2]=='*') {xx2=term.x2;yy2=term.y2;}
                else if(xx2==term.x1&&yy2==term.y1)
                {
                    if(a[xo1][yo1]=='*')
                    {
                        xx2=term.x2;
                        yy2=term.y2;
                    }
                }
            }
            if(dp[xx1][yy1][xx2][yy2]) continue;
            dp[xx1][yy1][xx2][yy2]=1;
            q.push(Node(xx1,yy1,xx2,yy2,term.time+1,term.tag1,term.tag2));
            }
    }
    return -1;
}
int main()
{
    int t;
    scanf("%d",&t);
    int x1,y1,x2,y2;

    while(t--)
    {
        int tag1=false;
        int tag2=false;
        scanf("%d%d",&n,&m);
        for(int i=0;i<n;i++)
            scanf("%s",a[i]);
        for(int i=0;i<n;i++)
        {
            for(int j=0;j<m;j++)
            {
                if(a[i][j]=='B')
                {
                    if(!tag1) {x1=i;y1=j;tag1=true;continue;}
                    if(!tag2) {x2=i;y2=j;tag2=true;}
                }
            }
        }
        while(!q.empty())
            q.pop();
        memset(dp,0,sizeof(dp));
        int ans=BFS(x1,y1,x2,y2);
        if(ans==-1)
        {
            printf("Sorry , sir , my poor program fails to get an answer.
");
        }
        else
            printf("%d
",ans);
    }
    return 0;
}