蒟蒻的代码
#include <bits/stdc++.h>
using namespace std;
unsigned long long s[25][25] = {0};
int n, m, a, b;
bool find(int x, int y){
x--;
y--;
if(x == a && y == b)
return true;
if(x == a+1 && y == b+2)
return true;
if(x == a+2 && y == b+1)
return true;
if(x == a+2 && y == b-1)
return true;
if(x == a+1 && y == b-2)
return true;
if(x == a-1 && y == b-2)
return true;
if(x == a-2 && y == b-1)
return true;
if(x == a-2 && y == b+1)
return true;
if(x == a-1 && y == b+2)
return true;
return false;
}
int main(){
cin >> n >> m >> a >> b;
for(int i = 1; i <= n+1; i++){
for(int j = 1; j <= m+1; j++){
if(i == 1 && j == 1){
s[i][j] = 1;
continue;
}
if(find(i, j))
continue;
else if(find(i-1, j))
s[i][j] = s[i][j-1];
else if(find(i, j-1))
s[i][j] = s[i-1][j];
else
s[i][j] = s[i][j-1]+s[i-1][j];
}
}
cout << s[m+1][n+1];
return 0;
}