RQNOJ过河卒问题

#include<stdio.h>
int main()
{
    int i,j,n,m,x,y;long long f[26][26];
    while(scanf("%d%d%d%d",&n,&m,&x,&y)!=EOF)
    {
         for(i=0,j=0;i<=n;i++)f[i][j]=1;
         for(i=0,j=0;j<=m;j++)f[i][j]=1;
         f[x][y]=0;
         if(x>=1&&y>=2)f[x-1][y-2]=0;
         if(x>=1&&y<=m-2)f[x-1][y+2]=0;
         if(x>=2&&y>=1)f[x-2][y-1]=0;
         if(x>=2&&y<=m-1)f[x-2][y+1]=0;
         if(x<=n-1&&y>=2)f[x+1][y-2]=0;
         if(x<=n-1&&y<=m-2)f[x+1][y+2]=0;
         if(x<=n-2&&y>=1)f[x+2][y-1]=0;
         if(x<=n-2&&y<=m-1)f[x+2][y+1]=0;
         for(i=1;i<=n;i++)
               for(j=1;j<=m;j++)
               {
                      if(f[i][j]!=0)f[i][j]=f[i-1][j]+f[i][j-1];
               }
         printf("%I64d\n",f[n][m]);
    }
}