> #include <iostream>
> #include <string>
> 
> using namespace std;
> 
> string f(string s1,string s2)
> {
> 	if(s1.length()==1) return s1;
> 	else if(s1.length()==0) return "";
> 	else
> 	{
> 		size_t m=s1.find(s2[0]);
> 		return f(s1.substr(0,m),s2.substr(1,m))+f(s1.substr(m+1),s2.substr(m+1))+s2[0];
> 	}
> }
> 
> int main()
> {
> 	string s1,s2,s;//s1为preorder traversal  s2为inorder traversal 
> 	while(cin>>s1>>s2)
> 	{
> 		s=f(s2,s1);
> 		cout<<s<<endl;
> 		
> 	}
> 
> 	return 0;
> }
> 
> 递归的思路是拿给的范例自己画了一下，运行范例OK就提交了，结果AC
 这代码写得太坑爹了