P1030 求先序排列

#include<cstdio>
#include<iostream>
#include<cstring>
using namespace std;
void beford(string in,string after)
{
	if(in.size()>0)
	{
		char ch=after[after.size()-1];
		cout<<ch;
		int k=in.find(ch);
		beford(in.substr(0,k),after.substr(0,k));
		beford(in.substr(k+1),after.substr(k,in.size()-k-1)); 
	}
}
int main()
{
	string inord,aftord;
	cin>>inord;cin>>aftord;
	beford(inord,aftord);
	cout<<endl;
	return 0;
}