zoj 1091 Knight Moves

/*中午又熬了，做出来了，还值得小高兴一下，呵呵

我的第一道宽度优先搜索

注意横纵坐标及从'a''1'开始的吧

感觉是个好题

不过不会c++很吃力啊*/

#include<stdio.h>

#include<stdlib.h>

#include<string.h>

#include<math.h>

int dir[8][2] = {{2,1},{2,-1},{-2,1},{-2,-1},{1,2},{1,-2},{-1,2},{-1,-2}};

int flag[8][8];

struct node

{

    int x,y,step;

}q[10000]; 

struct node N,P;

int main()

{

    char a,b,c,d;

   

    int front,rear,i;

    

    while(scanf(" %c%c %c%c",&a,&b,&c,&d)!=EOF)

    { 

        memset(flag,0,sizeof(flag));

        int c1 = a - 'a';

        int r1 = b - '1';

        int c2 = c - 'a';

        int r2 = d - '1';

        N.x = r1;

        N.y = c1;

        N.step = 0;

        flag[r1][c1] = 1;

        q[0] = N;

        front = 0;

        rear = 1;

        while(front < rear)

        {

            N = q[front++];

            if(N.x == r2  &&  N.y == c2)

                break;

            for(i=0;i<8;i++)

            {

                 int tx = N.x + dir[i][0];

                 int ty = N.y + dir[i][1];

                 if(tx>=0&&tx<8 && ty>=0&&ty<8 && flag[tx][ty]!=1)

                 {

                        P.x = tx;

                        P.y = ty;

                        P.step = N.step + 1;

                        q[rear++] = P;

                        flag[tx][ty] = 1;

                 }

            }

        }

        printf("To get from %c%c to %c%c takes %d knight moves.\n",a,b,c,d,N.step);



    }

    return 0;

}