HDU 1372 Knight Moves (BFS)

题目链接

又是边界。。。错了两次，从今天开始准备期末考试，明显挑战很大啊！

#include <stdio.h>

#include <string.h>

int p[20][20],o1[300],o2[300];

int main()

{

    int i,j,k,start,end,c0,r0;

    int num;

    int change1[9]= {1,1,-1,-1,2,2,-2,-2};

    int change2[9]= {2,-2,2,-2,1,-1,1,-1};

    char c1,r1,c2,r2;

    while(scanf("%c%c%*c%c%c%*c",&c1,&r1,&c2,&r2)!=EOF)

    {

        memset(p,0,sizeof(p));

        num = 0;

        o1[0] = c1 - 'a' + 1;

        o2[0] = r1 - '0';

        c0 = c2 - 'a' + 1;

        r0 = r2 - '0';

        p[o1[0]][o2[0]] = 1;

        start = end = 0;

        for(;;)

        {

            j = 1;

            if(p[c0][r0])break;

            for(i = start; i <= end; i ++)

            {

                for(k = 0; k <= 7; k ++)

                {

                    if(o1[i]+change1[k]<=8&&o1[i]+change1[k]>=1&&o2[i]+change2[k]<=8&&o2[i]+change2[k]>=1)

                    {

                        if(p[o1[i]+change1[k]][o2[i]+change2[k]] == 0)

                        {

                            o1[end+j] = o1[i]+change1[k];

                            o2[end+j] = o2[i]+change2[k];

                            j ++;

                            p[o1[i]+change1[k]][o2[i]+change2[k]] = 1;

                        }

                    }

                }

            }

            start = end + 1;

            end = end + j - 1;

            num ++;

        }

        printf("To get from %c%c to %c%c takes %d knight moves.\n",c1,r1,c2,r2,num);

    }

    return 0;

}