我的思路是像标数法一样去做

#include <bits/stdc++.h>
using namespace std;
int sx,sy,hx,hy;
int n,m;
int a[25][25],book[25][25];
int main()
{
	cin>>n>>m>>hx>>hy;
	//马能去的地方
	book[hx-1][hy-2]=1;
	book[hx-2][hy-1]=1;
	book[hx-2][hy+1]=1;
	book[hx-1][hy+2]=1;
	book[hx+1][hy+2]=1;
	book[hx+2][hy+1]=1;
	book[hx+2][hy-1]=1;
	book[hx+1][hy-2]=1;
	
	for(int i=0;i<n;i++)
		a[1][i]=1,a[i][1]=1;
	for(int i=0;i<n;i++)
	{
		for(int j=0;j<m;j++)
		{
			if(book[i][j]==1)//马能到
				a[i][j]=0;//0条走法
			else
				a[i][j]=a[i-1][j]+a[i][j-1];
		}
	}
	cout<<a[n-1][m-1];
	return 0;
}