比较坑的，注意数据范围，开long long
dp[i][j]表示到达(i,j)点的路径数

#include<bits/stdc++.h>
using namespace std;
#define int long long
int mp[30][30],dp[30][30];
signed main()
{
    int n,m,x,y;
    cin>>n>>m>>x>>y;
        mp[x-1][y-2]=1,mp[x-2][y-1]=1,mp[x-1][y+2]=1,mp[x-2][y+1]=1;
        mp[x+1][y-2]=1,mp[x+1][y+2]=1,mp[x+2][y-1]=1,mp[x+2][y+1]=1;
    mp[x][y]=1;
    dp[0][0]=1;//初始化
    for(int i=0;i<=n;i++)
    {
        for(int j=0;j<=m;j++)
        {
          if(!mp[i+1][j])     dp[i+1][j]+=dp[i][j];
          if(!mp[i][j+1])     dp[i][j+1]+=dp[i][j];
        }
    }
    cout<<dp[n][m];
}