大家都是WAon#4,而我ACon#4,WAon其他点

#include<bits/stdc++.h>
using namespace std;
const short dx[]={1,1,-1,-1,2,2,-2,-2};
const short dy[]={2,-2,2,-2,1,-1,1,-1};
const short d1[]={1,0};
const short d2[]={0,1};
typedef long long l;
l dp[22][22];
bool b[22][22];
int main()
{
	memset(b,false,sizeof(b));
	dp[1][1]=1;
	unsigned short ax,ay,bx,by;
	scanf("%hu%hu%hu%hu",&ax,&ay,&bx,&by);
	for(unsigned short i=0;i<8;i++)
	{
		if(bx+dx[i]<=ax&&by+dx[i]<=ay&&bx+dx[i]>=1&&by+dy[i]>=1) b[bx+dx[i]][by+dy[i]]=true;
	}
	b[bx][by]=true;
	for(unsigned short i=1;i<=ax;i++)
	{
		for(unsigned short j=1;j<=ay;j++)
		{

			if(!b[i][j])
			{
				if(i>1) dp[i][j]+=dp[i-1][j];
				if(j>1) dp[i][j]+=dp[i][j-1];
			}	
		}
	}
	printf("%lld\n",dp[ax][ay]);
	return 0;
}