求，未知错误

#include<cstdio>
#include<cstring>
long long s[101][101];
long long k[101][101];
long long a,b,x,y;
int main()
{
    memset(s,0,sizeof(s));
    scanf("%lld %lld %lld %lld",&x,&y,&a,&b);
    s[0][0]=1;
    k[a-2][b-1]=-1;
    k[a-2][b+1]=-1;
    k[a+2][b-1]=-1;
    k[a+2][b+1]=-1;
    k[a-1][b-2]=-1;
    k[a-1][b+2]=-1;
    k[a+1][b-2]=-1;
    k[a+1][b+2]=-1;
    k[a][b]=-1;
    for(int i=0;i<=x;i++)
    {
        for(int j=0;j<=y;j++)
        {
            if(k[i][j]==-1)
            {
                continue;
            }
            if(i==0 && j==0)
                s[i][j]+=s[i-1][j]+s[i][j-1];
            else
            {
                if(i==0)
                {
                    s[i][j]+=s[i][j-1];
                }
                if(j==0)
                {
                    s[i][j]+=s[i-1][j];
                }
            }
            if(i!=0&&j!=0)
                s[i][j]+=s[i-1][j]+s[i][j-1];
        }
    }
    printf("%lld",s[x][y]);
    return 0;
}