题解:从中心出发,减到边就算一种,两个方向反向减,关于两点的 位置中心对称

AC代码如下:

#include<iostream>
#include<algorithm>
#include<cstring>
using namespace std;

int book[8][8],nex1[4][2]={0,1,1,0,0,-1,-1,0},nex2[4][2]={0,-1,-1,0,0,1,1,0},cnt;

bool judge(int x,int y)
{
	if(x<=0||x>=6||y<=0||y>=6)
		return true;
	return false;
}

void dfs(int x,int y,int nx,int ny)
{
	if(judge(x,y))
	{
		cnt++;
		return ;
	}
	int i,xiax,xiay,a,b;
	for(i=0;i<4;i++)
	{
		xiax=x+nex1[i][0];
		xiay=y+nex1[i][1];
		a=nx+nex2[i][0];
		b=ny+nex2[i][1];
		if(book[xiax][xiay]==0 && book[a][b]==0)
		{
			book[xiax][xiay]=1;
			book[a][b]=1;
			dfs(xiax,xiay,a,b);
			book[xiax][xiay]=0;
			book[a][b]=0;
		}
	}
	return ;
}

int main()
{
	memset(book,0,sizeof(book));
	cnt=0;
	book[3][3]=1;
	dfs(3,3,3,3);
	cout<<cnt/4<<endl;
}
answer:509