#include <iostream>
#include <cstdlib>
#include <fstream>

using namespace std;

struct Node
{
    int data;
    Node *firstChild;
    Node *nextSibling;
    Node(int d, Node *f, Node *n)
    {
        data=d;
        firstChild=f;
        nextSibling=n;
    }
};

typedef struct TreeADT *Tree;
struct TreeADT
{
    Node *root;
};

void createTop(Node *p, Node *pp, int arr[], int index, int n)
{
    if (arr[index]==pp->data)
    {
        Node *pt = new Node(arr[index+1],NULL,NULL);
        pp->firstChild=pt;
        createTop(pp,pt,arr,index+2,n);
    }
    for (int i=index;i<n;i=i+2)
    {
        if (arr[i]==p->data)
        {
            Node *pt= new Node(arr[i+1],NULL,NULL);
            pp->nextSibling=pt;
            createTop(p,pt,arr,i+2,n);
            break;
        }
    }
}

Tree createTree(char *filename)
{
    ifstream input(filename);
    Tree list = new TreeADT;
    list->root=NULL;

    if (!input.is_open())
        cout<<"Khong the mo file"<<endl;
    else
    {
        int n=0, arr[100];
        while (input>>arr[n])
            n++;
        Node *p = new Node(arr[0],NULL,NULL);
        Node *pp = new Node(arr[1],NULL,NULL);
        p->firstChild=pp;
        createTop(p,pp,arr,2,n);
        list->root=p;
    }
    return list;
}

void Preorder(Tree t)
{
    if (t->root!=NULL)
    {
        cout<<" "<<t->root->data;
        Tree p = new TreeADT;
        p->root=t->root->firstChild;
        while (p->root!=NULL)
        {
            Preorder(p);
            p->root=p->root->nextSibling;
        }
    }
}

void Postorder(Tree t)
{
    if (t->root!=NULL)
    {
        Tree p = new TreeADT;
        p->root=t->root->firstChild;
        while (p->root!=NULL)
        {
            Postorder(p);
            p->root=p->root->nextSibling;
        }
        cout<<" "<<t->root->data;
    }
}

int main(int argc, char const *argv[])
{
    char filename[]="data_01.txt";
    Tree t=createTree(filename);
    Preorder(t);
    return 0;
}