2013杭州现场赛B题-Rabbit Kingdom

杭州现场赛的题。BFS+DFS

 

 

#include <iostream>
#include<cstdio>
#include<cstring>
#define inf 9999999
using namespace std;

char mp[105][105];
int sq[5][5];
int step[4][2]={{0,1},{1,0},{0,-1},{-1,0}};
struct pos
{
    int x,y;
};

int n,m,prn,x,y,tmp,ans,cnt;
bool viss[5];
int bfs(pos bg,pos ed)
{
    int i;
    pos que[20000];
    int front=0,rear=1;
    bool vis[105][105]={false};
    vis[bg.x][bg.y]=true;
    que[0]=bg;
    int cnt[20000]={0};
    if(ed.x==bg.x&&ed.y==bg.y)
        return 0;
    while(rear>front)
    {
        for(i=0;i<4;i++)
        {
            if(que[front].x+step[i][0]>=0&&que[front].x+step[i][0]<n&&que[front].y+step[i][1]>=0&&que[front].y+step[i][1]<m&&
               mp[que[front].x+step[i][0]][que[front].y+step[i][1]]!='#'&&!vis[que[front].x+step[i][0]][que[front].y+step[i][1]])
            {
                que[rear].x=que[front].x+step[i][0];
                que[rear].y=que[front].y+step[i][1];
                vis[que[rear].x][que[rear].y]=true;
                cnt[rear]=cnt[front]+1;
                if(que[rear].x==ed.x&&que[rear].y==ed.y)
                    return cnt[rear];
//                cout<<que[rear].x<<' '<<que[rear].y<<endl;
                rear++;
            }
        }
        front++;
    }
    return -1;
}
void cal(int q)
{
    int i;
    if(cnt==prn)
        return;
    viss[q]=true;
    for(i=1;i<=prn;i++)
    {
        if(!viss[i])
        {
            tmp+=sq[q][i];
            viss[i]=true;
            cnt++;
            cal(i);
            if(cnt==prn)
                if(tmp<ans)
                    ans=tmp;
            cnt--;
            tmp-=sq[q][i];
            viss[i]=false;
        }
    }
    viss[q]=false;
    return;
}
int main()
{
//    freopen("in.txt","r",stdin);
    while(cin>>n>>m&&(n+m))
    {
        memset(sq,0,sizeof(sq));
        memset(viss,false,sizeof(viss));
        int i,j;
        ans=inf;
        tmp=0;
        cnt=0;
        pos st;
        for(i=0;i<n;i++)
        {
            for(j=0;j<m;j++)
            {
                cin>>mp[i][j];
                if(mp[i][j]=='@')
                {
                    st.x=i;
                    st.y=j;
                }
            }
        }
        cin>>prn;
        pos pr[4];
        for(i=0;i<prn;i++)
        {
            cin>>pr[i].x>>pr[i].y;
            pr[i].x--;
            pr[i].y--;
//            cout<<pr[i].x<<"   "<<pr[i].y<<endl;
        }
        bool f=true;
        for(i=0;i<prn;i++)
        {
            sq[0][i+1]=bfs(st,pr[i]);
            if(sq[0][i+1]==-1)
            {
                f=false;
                break;
            }
        }
        if(!f)
        {
            cout<<-1<<endl;
            continue;
        }
        for(i=0;i<prn;i++)
        {
            for(j=0;j<prn;j++)
            {
                if(i==j)
                    continue;
                int t=bfs(pr[i],pr[j]);
                sq[i+1][j+1]=sq[j+1][i+1]=t;
            }
        }
        cal(0);
        cout<<ans<<endl;
    }
    return 0;
}