BFS

代码：

#include <stdio.h>
#include <malloc.h>
#include <string.h>

typedef struct node
{
    int x;
    int y;
    int s;
}node;

int N,M;
int R,C;
int S,K;
int *chess = NULL;
//int *book = NULL;
node *que = NULL;

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

int main(void)
{
    int tc, T;

    setbuf(stdout, NULL);

    scanf("%d", &T);
    for(tc = 0; tc < T; tc++)
    {
        
        /**********************************
        *  Implement your algorithm here. *
        ***********************************/
        scanf("%d%d",&N,&M);

        //chess = (int *)malloc(sizeof(int)*(N+1)*(M+1));
        //memset(chess,0,sizeof(chess));

        //int *book = (int *)malloc(sizeof(int)*(N+1)*(M+1));
        //memset(book,0,sizeof(book));
        int book[101][101]={0};
        
        que = (node *)malloc(sizeof(node)*N*M+1);
        memset(que,0,sizeof(que));

        scanf("%d%d",&R,&C);
        scanf("%d%d",&S,&K);

        int head = 1;
        int tail = 1;
        
        que[tail].x = R;
        que[tail].y = C;
        que[tail].s = 0;
        book[R][C]=1;


        tail++;
        
        int flag = 0;
        int k = 0;
        int qx,qy;

        while(head<tail)
        {
            for(k = 0; k < 8; k++)
            {
                qx=    que[head].x+dirction[k][0];    
                qy=    que[head].y+dirction[k][1];

                if(qx<1 || qy< 1 || qx > M || qy >N)
                    continue;

                if(book[qx][qy] == 0)
                {
                    book[qx][qy] = 1;
                    que[tail].x = qx;
                    que[tail].y = qy;
                    que[tail].s = que[head].s+1;
                    
                    tail++;
                }
                //printf("%d, %d, %d
",que[tail-1].x,que[tail-1].y,que[tail-1].s);
                if(qx== S && qy== K)
                {
                    flag = 1;
                    break;
                }
            }
            
            if(flag == 1)
            {
                break;
            }

            head++;
        }
        
        
        printf("%d
",que[tail-1].s);
        // Print the answer to standard output(screen).
        
    }

    return 0;//Your program should return 0 on normal termination.
}

测试数据：

2
9 9
3 5 2 8
20 20
2 3 7 9

测试结果：

2

5