https://www.luogu.com.cn/problem/P1644

#include<bits/stdc++.h>
using namespace std;
int m,n,s;
void t(int x,int y){
	if(x+2<m&&y+1<n&&y>=0){
		s++;
//		cout<<x<<" "<<y<<endl;
		t(x+2,y+1);
	}
	if(x+1<m&&y+2<n&&y>=0){
		s++;
//		cout<<x<<" "<<y<<endl;
		t(x+1,y+2);
	}
	if(x+2<m&&y-1<n&&y>=0){
		s++;
//		cout<<x<<" "<<y<<endl;
		t(x+2,y-1);
	}
	if(x+1<m&&y-2<n&&y>=0){
		s++;
//		cout<<x<<" "<<y<<endl;
		t(x+1,y-2);
	}
}
int main(){
	cin>>m>>n;
	t(0,0);
	cout<<s<<endl;
	return 0;
}

帮助必关（可能有延迟，因为去过年不在线）