439骑士走到固定位置最短路程

#include <iostream>
#include <cstring>
#include <cstdio>
#define MAX 10

using namespace std;

int q[MAX*MAX]; //·½¸ñ
int dist[MAX][MAX]; // ¾àÀë
int vis[MAX][MAX];
int dx[] = {-1,-2,-2,-1,1,2,2,1};
int dy[] = {-2,-1,1,2,2,1,-1,-2};

int bfs(int x,int y,int a,int b)
{
    if(x == a && y == b) return 0;
    memset(vis,0,sizeof(vis));
    int front = 0,rear = 0,u;
    u = x * 8 + y;

    dist[x][y] = 0;

    q[rear++] = u;

    while(front < rear)
    {
        u = q[front++];
        x = u / 8; y = u % 8;
        if( y == 0) {y = 8;x = x-1;};
        for(int i = 0;i < 8;i++)
        {
            int nx = x+dx[i],ny = y+dy[i];
            if(nx >0 && nx <= 8 && ny > 0 && ny <=8 && !vis[nx][ny])
            {
                int v = nx*8 + ny;
                q[rear++] = v;
                vis[nx][ny] = 1;
                dist[nx][ny] = dist[x][y] + 1;

                if(nx == a && ny == b) return dist[a][b];
            }
        }
    }
}

int main()
{
   // freopen("in.in","r",stdin);
    char x[3],y[3];
    while(scanf("%s%s",x,y) == 2)
    {
        int count;
        if(x[0] < y[0] || (x[0] == y[0] && x[1] <= y[1])){
            count = bfs(y[1]-'0',y[0]-'a'+1,x[1]-'0',x[0]-'a'+1);
        }
        else{
            count = bfs(x[1]-'0',x[0]-'a'+1,y[1]-'0',y[0]-'a'+1);
        }
        printf("To get from %s to %s takes %d knight moves.\n",x,y,count);
    }
}