poj 2243 Knight Moves

这题和poj 1915一样，用bfs做走马步。现在再看当时的代码，真是好幼稚啊。

#include <stdio.h>
#include <string.h>
int X[] = {-2,-2,-1,-1,1,1,2,2},
    Y[] = {-1,1,-2,2,-2,2,-1,1};
struct Point
{
    int x,y;
    void init(int a,int b)
    {x = a; y = b;}
}q[70],s,t;
int head,tail,map[9][9];
void bfs()
{
    Point u,v;
    int x1,y1,i;
    head = tail = 0;
    q[0] = s;
    map[s.x][s.y] = 0;
    if(s.x == t.x && s.y == t.y)
    {
        printf("To get from %c%d to %c%d takes 0 knight moves.\n"
            ,s.x-1+'a',s.y,t.x-1+'a',t.y);
        return ;
    }
    while(head <= tail)
    {
        u = q[head++];
        for(i = 0; i < 8; i++)
        {
            x1 = u.x + X[i];
            y1 = u.y + Y[i];
            if(x1 > 0 && x1 < 9 && y1 > 0 && y1 < 9 && map[x1][y1] == -1)
            {
                if(x1 == t.x && y1 == t.y)
                {    printf("To get from %c%d to %c%d takes %d knight moves.\n"
                    ,s.x-1+'a',s.y,t.x-1+'a',t.y,map[u.x][u.y]+1);return ;}
                v.init(x1,y1);
                q[++tail] = v;
                map[x1][y1] = map[u.x][u.y] + 1;
            }
        }
    }
}
int main()
{
    char t1,t2;
    while(~scanf("%c%d %c%d",&t1,&s.y,&t2,&t.y))
    {
        getchar();
        s.x = t1 -'a'+1;
        t.x = t2 -'a'+1;
        memset(map,-1,sizeof map);
        bfs();
    }
    return 0;
}