天天写算法之Catch him

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这个题就是判断边界的时候需要判断一个整体，其他的时候没什么区别。主要区别在于判断越界，判断是否访问过。依旧是BFS

#include<iostream>
#include<cstring>
#include<cstdio>
#include<queue>
#define inf 0x3f3f3f3f
#define MAX 110
#define repf(i,from ,to) for(int i =from ; i <to ; i++)
using namespace std;
char Map[MAX][MAX];
int Vis[MAX][MAX];
int n,m,time ,magicNum;
int dir[4][2]={{0,1,},{0,-1},{1,0},{-1,0}};


struct Node {
    int X[21],Y[21];
    int num ;
    int time ;
    friend bool operator <(Node a ,Node b)
    {
        return a.time>b.time ;
    }

};
bool inMap(int x ,int y)
{
    if(x<0||x>=n||y<0||y>=m)
        return false ;
    return true ;
}

int dfs(Node start)
{
    memset(Vis,0,sizeof(Vis));
    Vis[start.X[0]][start.Y[0]]=1;
    Node now ,next ;
    priority_queue<Node> Q;
    Q.push(start);
    while (!Q.empty())
    {

     now = Q.top();
     Q.pop();

     repf(i,0,now.num)
     {
         if( Map[now.X[i]][now.Y[i]]== 'Q')
         {
             return now.time;
         }
     }
     for(int i = 0 ;i< 4; i ++)
     {
         next = now ;
         bool flag = true ;
         repf(j , 0 ,now.num)
         {
            next.X[j] = now.X[j]+dir[i][0];
            next.Y[j] = now.Y[j]+dir[i][1];
         //   cout << next.X[j] <<" " << next.Y[j]<<endl;
            if(!inMap(next.X[j],next.Y[j])||Map[next.X[j]][next.Y[j]]=='O')
            {
                flag = false ;
                break;
            }
         }
         if(!flag)
         {
            continue ;
         }

         if(!Vis[next.X[0]][next.Y[0]])
         {
             Vis[next.X[0]][next.Y[0]] = 1 ;
             next.time++;
             Q.push(next);
         }

     }



    }
    return -1;
}

int main()
{
    Node start ;
    while (cin>>n>>m)
    {
        if(m==0&&n==0) break ;
        int index = 0 ;
        repf(i,0,n)
        {
            repf(j,0,m)
            {
                cin>>Map[i][j];
                if(Map[i][j]=='D')
                {
                    start.X[index]=i;
                    start.Y[index++]=j;
                }
            }
        }
        start.num = index ;
        start.time = 0;

        int res = dfs(start);
        if(res==-1)
        {
            cout <<"Impossible"<<endl;
        }else {
            cout << res<<endl;
        }
    }

}