60分求调玄关

#include<bits/stdc++.h>
using namespace std;
int n, m, x, y;
long long dp[30][30];
bool horse[30][30];
bool chack(int i, int j){
	return i >= 0 && j >= 0 && i <= n && y <= m;
}
int main(){
	cin>>n>>m>>x>>y;
	if(chack(x, y)) horse[x][y] = true;
	if(chack(x + 2, y + 1)) horse[x + 2][y + 1] = true;
	if(chack(x + 2, y - 1)) horse[x + 2][y - 1] = true;
	if(chack(x - 2, y + 1)) horse[x - 2][y + 1] = true;
	if(chack(x - 2, y - 1)) horse[x - 2][y - 1] = true;
	if(chack(x + 1, y + 2)) horse[x + 1][y + 2] = true;
	if(chack(x + 1, y - 2)) horse[x + 1][y - 2] = true;
	if(chack(x - 1, y + 2)) horse[x - 1][y + 2] = true;
	if(chack(x - 1, y - 2)) horse[x - 1][y - 2] = true;
	for(int i = 0;i <= n;i ++){
		for(int j = 0;j <= m;j ++){
			if(horse[i][j]){
				dp[i][j] = 0;
				continue;
			}
			if(i == 0 || j == 0){
				dp[i][j] = 1;
				continue;
			}
			dp[i][j] = dp[i - 1][j] + dp[i][j - 1];
		}
	}
	
	cout<<dp[n][m];
}