uva 439 Knight Moves 骑士移动 —— bfs

代码如下：

#include<stdio.h>//bfs 骑士的移动
#include<string.h>
#include<stdlib.h>

struct
{
    int x,y,z;
}q[1000];
int map[10][10],head = 0, tail = 0;
int d[8][2]={ {-1,-2}, {-1,2}, {1,-2}, {1,2}, {-2,-1}, {-2,1}, {2,-1}, {2,1} };

int bfs(int x,int y,int xo,int yo)
{
    if(x==xo && y==yo)
        return 0;

    q[tail].x = x; q[tail].y = y; tail++; map[x][y] = 1;
    while(tail!=head)
    {
        for(int i = 0;i<8;i++)
        {
            int xx = q[head].x + d[i][0];
            int yy = q[head].y + d[i][1];
            if(!map[xx][yy] && xx>0 && xx<9 && yy>0 && yy<9)
            {
                if(xx==xo && yy==yo)
                    return q[head].z+1;
                map[xx][yy] = 1;
                q[tail].x = xx; q[tail].y = yy; q[tail].z = q[head].z+1; tail++;
            }
        }
        head++;
    }
    return -1;
}

int main()
{
    int x,y,xo,yo,step;
    memset(map,0,sizeof(map));
    memset(q,0,sizeof(q));
    scanf("%d %d %d %d",&x,&y,&xo,&yo);
    step = bfs(x,y,xo,yo);
    step>=0? printf("%d",step):printf("no way");
    return 0;
}