hdu 1372(simple BFS)

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This is a basic BFS problem.But the way of knight's move  is strange,if you don't know the law of the knight's move,you are likely to cann't work the problem out.However,if you can find the regularity of the problem from the given cases's data,you must be very smart!

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#include<iostream> #include<queue> #include<string> using namespace std; int map[10][10]; char s1[5],s2[5]; int visted[10][10]; int x1,y1; int x2,y2; int dir[8][2]={1,2,-1,2,1,-2,-1,-2,2,1,2,-1,-2,1,-2,-1}; struct node {     int x,y,step; }; void BFS() {     int x,y;     node cur,next;     queue<node>q;     memset(visted,0,sizeof(visted));     cur.x=x1;     cur.y=y1;     cur.step=0;     visted[x1][y1]=1;     q.push(cur);     while(!q.empty())     {         cur=q.front();         q.pop();         if(cur.x==x2&&cur.y==y2)         {             printf("To get from %s to %s takes %d knight moves.\n",s1,s2,cur.step);             return ;         }         for(int i=0;i<8;i++)         {             next.x=x=cur.x+dir[i][0];             next.y=y=cur.y+dir[i][1];             next.step=cur.step+1;             if(x>=0&&x<8&&y>=0&&y<8)             {                 visted[x][y]=1;                 q.push(next);             }           }     } }     int main() {           while(scanf("%s%s",s1,s2)!=EOF)     {         x1=s1[0]-'a';         y1=s1[1]-'1';         x2=s2[0]-'a';         y2=s2[1]-'1';         BFS();     }     return 0; }