HDU 1372

http://acm.hdu.edu.cn/showproblem.php?pid=1372

象棋中给出起点到终点，马最少走几步？马走日子 ,基础的BFS

代码：

#include<iostream>
#include<queue>
#include<string>
#include<cstring>
#include<cstdio>
using namespace std;
int a[10][10], visit[10][10];
int bx,by,ex,ey;
int XX[8][2]={{-2,-1},{-1,-2},{1,-2},{2,-1},{-2,1},{-1,2},{1,2},{2,1}};
struct node{int x,y,step;};
int BFS(int step)
{
    if(bx==ex&&by==ey)return step;
    int k,xx,yy,stepp;
    queue<node>qu;
    node t,tt;
    t.x=bx,t.y=by,t.step=0;
    qu.push(t);
    while(!qu.empty())
    {
        t=qu.front();
        qu.pop();
        for(k=0;k<8;k++)
        {
            xx=t.x+XX[k][0],yy=t.y+XX[k][1],stepp=t.step;
            if(xx>0&&xx<=8&&yy>0&&yy<=8&&!visit[xx][yy])
            {
                visit[xx][yy]=1;
                stepp++;
                if(xx==ex&&yy==ey)return stepp;
                tt.x=xx, tt.y=yy,tt.step=stepp;
                qu.push(tt);
            }
        }
    }
    return -1;

}

int main()
{
   char ch1,ch2;
   int beg,end;
   while(cin>>ch1>>beg>>ch2>>end)
   {
       bx=ch1-'a'+1, by=beg;
       ex=ch2-'a'+1, ey=end;
       memset(visit,0,sizeof(visit));
       visit[bx][by]=1;
       int step=BFS(0);
       cout<<"To get from "<<ch1<<beg<<" to "<<ch2
         <<end<<" takes "<<step<<" knight moves."<<endl;

   }
   return 0;
}