BUNOJ 4044

#include <iostream>
#include <string>
using namespace std;
typedef struct Node
{
    char data;
    Node *lchild,*rchild;
}Node,*Bitree;
Bitree creat(string s1,string s2)
{  
    if(s1.length()==0)
        return NULL;
    Node *root;
    root = new Node;
    root->data = s1[0];//第二次做，竟然忘家了 
    size_t pos = s2.find(s1[0]);
    root->lchild=creat(s1.substr(1,pos),s2.substr(0,pos));//从index开始，共num个字符，不是到第num 
    root->rchild=creat(s1.substr(pos+1),s2.substr(pos+1));
    return root;
}
void postorder(Node *root)
{
    if(root)
    {
        postorder(root->lchild);
        postorder(root->rchild);
        cout<<root->data;
    }
}
int main()
{
    int i,j,k;
    string s1,s2;
    while(cin>>s1>>s2)
    {
        Node *root;
        root = creat(s1,s2);
        postorder(root);
        cout<<endl;
    }
    return 0;
}