#include <iostream>

 #include <vector>

 #include <algorithm>

 #include <queue>

 #include <stack>

 #include <string>

 #include <fstream>

 using namespace std;

 struct node {

     char data;

     struct node *left, *right;

     node() : data(), left(NULL), right(NULL) { }

     node(int d) : data(d), left(NULL), right(NULL) { }

 };

 void prints(node *root) {

     if (!root) return;

     prints(root->left);

     cout << root->data << " ";

     prints(root->right);

 }

 node *buildtree(char in[], char pre[], int beg, int end) {

     static int preindex = ;

     if (beg > end) return NULL;

     node *root = new node(pre[preindex++]);

     int index = beg;

     for (int i = beg; i <= end; i++) {

         if (in[i] == root->data) {

             index = i;

             break;

         }

     }

     root->left = buildtree(in, pre, beg, index-);

     root->right = buildtree(in, pre, index+, end);

     return root;

 }

 int main() {

     char in[] = {'D', 'B', 'E', 'A', 'F', 'C'};

     char pre[] = {'A', 'B', 'D', 'E', 'C', 'F'};

     int len = ;

     node *root = buildtree(in, pre, , len-);

     prints(root);

     return ;

 }