#include<iostream>
#include<queue>
#include<vector>
#include<stack>
using namespace std;
struct TreeNode {
  int val;
  struct TreeNode *left;
  struct TreeNode *right;
  TreeNode(int x) :
    val(x), left(NULL), right(NULL) {
  }
};
void PreOrder(TreeNode *T)//前序遍历
{
  if (!T)
    return;
  if (T)
  {
    cout << T->val<<endl;
    PreOrder(T->left);
    PreOrder(T->right);
  }
  
}
void PreOrder(TreeNode *T)//非递归，前序遍历
{
  if (T == NULL)
  {
    return;
  }
  stack<TreeNode*>s;
  s.push(T);
  TreeNode *temp;
  while (!s.empty())
  {
    temp = s.top();
    cout << temp->val;
    s.pop();
    if (temp->left)
    {
      s.push(temp->left);
    }
    if (temp->right)
    {
      s.push(temp->right);
    }
  }
}
 
void InOrder(TreeNode *T)//中序遍历
{
  if (!T)
    return;
  InOrder(T->left);
  cout << T->val;
  InOrder(T->right);
}
 
void PostOrder(TreeNode *T)//后序遍历
{
  if (!T)
    return;
  PostOrder(T->left);
  PostOrder(T->right);
  cout << T->val;
}
void Levelorder(TreeNode *T)//层析遍历
{
  if (!T)
    return;
  TreeNode *temp;
  queue<TreeNode*>q;
  q.push(T);
  while (!q.empty())
  {
    temp = q.front();
    cout << temp->val;
    if (temp->left)
      q.push(temp->left);
    if (temp->right)
      q.push(temp->right);
    q.pop();
  }
}
void DeepOrder(TreeNode *T)//深度遍历
{
  if (!T)
    return;
  TreeNode *temp;
  stack<TreeNode*>s;
  s.push(T);
  while (!s.empty())
  {
    temp = s.top();
    cout << temp->val;
    s.pop();
    if (temp->left)
      s.push(temp->left);
    if (temp->right)
      s.push(temp->right);
  }
}