骑士问题

/*骑士问题*/#include <iostream>#include <string>//#include <fstream>#include <queue>using namespace std;#define MAX 12typedef struct _point{        int x;        int y;        int dep;}point;int map[MAX][MAX];int p[][2]={{-1,-2},{-2,-1},{-2,1},{-1,2},{1,2},{2,1},{2,-1},{1,-2}};point start,end;//fstream fin;int bfs();int main(){     //fin.open("2585.txt",ios::in);   int times=0;   int b;   while(cin>>b)   {       if(b==-1) break;       for(int i=0;i<12;i++)          for(int j=0;j<12;j++)             map[i][j]=1;       //周围围上栅栏        for(int i=2;i<10;i++)          for(int j=2;j<10;j++)            map[i][j]=0;              string a;       for(int i=0;i<b;i++)       {                cin>>a;                map[a[0]-'a'+2][(a[1]-'1')+2]=1;       }          cin>>a;       start.x=a[0]-'a'+2;       start.y=a[1]-'1'+2;       start.dep=0;                     cin>>a;       end.x=a[0]-'a'+2;       end.y=a[1]-'1'+2;              int dep=bfs();       if(dep)         cout<<"Board "<<++times<<":"<<dep<<" moves"<<endl;        else          cout<<"Board "<<++times<<":not reachable"<<endl;   }   system("pause");   return 0;}int bfs(){    int dep=0;    queue<point> Q;    Q.push(start);    while(!Q.empty())    {          //当前是的dep            for(int i=0;i<8;i++)           {                   point cur=Q.front();                   if(map[cur.x+p[i][0]][cur.y+p[i][1]]==0)                   {                         if(end.x==cur.x+p[i][0]&&cur.y+p[i][1]==end.y)                         {                              end.dep=cur.dep+1;                              return end.dep;                         }                         map[cur.x+p[i][0]][cur.y+p[i][1]]=1;                         point temp;                         temp.x=cur.x+p[i][0];                         temp.y=cur.y+p[i][1];                         temp.dep=cur.dep+1;                         Q.push(temp);                   }           }                     Q.pop();             }    return 0;}