@[fzx纯数孤傲](/user/376161) 我的代码：
```cpp
#include <iostream>
using namespace std;
int e[2],h[2];
bool isHorse(int x,int y){
if(x==h[0]&&y==h[1]){
return true;
}
if(x==h[0]-1 || x==h[0]+1){
if(y==h[1]-2 || y==h[1]+2){
return true;
}
}else if(x==h[0]-2 || x==h[0]+2){
if(y==h[1]-1 || y==h[1]+1){
return true;
}
}
return false;
}
int main(){
cin >> e[0] >> e[1] >> h[0] >> h[1];
long long board[21][21]={0};
for(int i=0;i<=e[1];i++){
for(int j=0;j<=e[0];j++){
if(isHorse(j,i)){
board[j][i]=0;
}else if(i==0&&j==0){
board[j][i]=1;
}else if(i==0){
board[j][i]=board[j-1][i];
}else if(j==0){
board[j][i]=board[j][i-1];
}else{
board[j][i]=board[j-1][i]+board[j][i-1];
}
}
}
cout << board[e[0]][e[1]] << endl;
return 0;
}
```
by bykem @ 2020-08-24 20:11:52