#include <iostream>
#include <cstdio>
#include <queue>
#include <stack>
#include <cstring>
using namespace std;

typedef struct NODE{
	NODE()
	:key('0'), lchild(NULL), rchild(NULL){}
	char key;
	NODE *lchild;
	NODE *rchild;
} Node;

void pre_mid(Node *&node, int len, char *pre, char *mid){
	if(len <= 0) return;
	node = new Node();
	node->key = *pre;
	char *pm = strchr(mid, *pre);
	int l_len = pm - mid;
	int r_len = len - l_len - 1;
	pre_mid(node->lchild, l_len, pre+1, mid);
	pre_mid(node->rchild, r_len, pre+l_len+1, pm+1);
}

void mid_after(Node *&node, int len, char *mid, char *after){
	if(len <= 0) return;
	node = new Node();
	node->key = *(after+len-1);
	char *pm = strchr(mid, node->key);
	int l_len = pm - mid;
	int r_len = len - l_len - 1;
	mid_after(node->lchild, l_len, mid, after);
	mid_after(node->rchild, r_len, pm+1, after+l_len);
}

void preorder(Node *node){
	if(node == NULL) return;
	stack<Node *> st;
	st.push(node);
	while(!st.empty()){
		Node *cur = st.top();
		st.pop();
		cout << cur->key;
		if(cur->rchild)
			st.push(cur->rchild);
		if(cur->lchild)
			st.push(cur->lchild);
	}
	cout << endl;
}

void midorder(Node *node){
	if(node == NULL) return;
	stack<Node *> st;
	Node *cur = node;
	while(cur || !st.empty()){
		while(cur){
			st.push(cur);
			cur = cur->lchild;
		}
		if(!st.empty()){
			cur = st.top();
			st.pop();
			cout << cur->key;
			cur = cur->rchild;
		}
	}
	cout << endl;
}

typedef struct POINT{
	POINT():node(NULL), flag(false){}
	POINT(Node *_node = NULL, int _flag = false)
		:node(_node), flag(_flag)
	{}
	Node *node;
	bool flag;
} Point;

void afterorder(Node *node){
	if(node == NULL) return;
	stack<Point> st;
	st.push(Point(node, false));
	while(!st.empty()){
		Point &cur = st.top();
		if(cur.flag){
			cout << cur.node->key;
			st.pop();
			continue;
		}
		if(cur.node->rchild)
			st.push(Point(cur.node->rchild, false));
		if(cur.node->lchild)
			st.push(Point(cur.node->lchild, false));
		cur.flag = true;
	}
	cout << endl;
}

int main()
{
	Node *root = NULL;
	char *pre = "DBACEGF";
	char *mid = "ABCDEFG";
	char *after = "ACBFGED";
	pre_mid(root, strlen(pre), pre, mid);
	mid_after(root, strlen(pre), mid, after);
	preorder(root);
	midorder(root);
	afterorder(root);
	return 0;
}