```cpp
#include <iostream>
#include <bits/stdc++.h>
using namespace std;
long long flag[1001][1001];
long long a[1001][1001];
long long bx,by;
long long ma,mb;
int main () {
cin >> by >> bx;
cin >> ma >> mb;
for (int i = 0; i <= by; i++) {
a[i][0] = 1;
}
for (int i = 0; i <= bx; i++) {
a[0][i] = 1;
}
flag[ma][mb] = 1;
flag[ma - 1][mb - 2] = 1;
flag[ma - 1][mb + 2] = 1;
flag[ma + 1][mb - 2] = 1;
flag[ma + 1][mb + 2] = 1;
flag[ma - 2][mb - 1] = 1;
flag[ma - 2][mb + 1] = 1;
flag[ma + 2][mb - 1] = 1;
flag[ma + 2][mb + 1] = 1;
for (int i = 1; i <= by ; i++) {
for (int j = 1; j <= bx; j++) {
if (flag[i][j] != 1) {
a[i][j] = a[i][j - 1] + a[i - 1][j];
}
else {
a[i][j] = 0;
}
}
}
cout << a[by][bx];
return 0;
}
```
by hanran_ @ 2021-07-07 12:02:52
马的坐标可能在0上（0， 4），那ma-2或mb-2就越界了 @[云起雾饶](/user/260361)
by kakashi263 @ 2021-07-09 20:36:19