二叉树构建、删除、遍历、求深度、求节点数

//Notice: this file.cpp can run on your pc;
//input: example
//    1
// 2      3
// you can input 1 2 0 0 3 0 0 
// then you'll get a binaryTree like line 3、4 

#include <iostream>
#include <stdlib.h>
using namespace std;
typedef struct BinaryTreeNode{
  int data;
  BinaryTreeNode *left;
  BinaryTreeNode *right;
}BinaryTreeNode;


BinaryTreeNode* createBinaryTree(){
  BinaryTreeNode *p;
  int a;
  cin >> a;
  if(a==0){
    p = NULL;
  }else{
    p = (BinaryTreeNode*)malloc(sizeof(BinaryTreeNode));
    p->data = a;
    p->left = createBinaryTree();
    p->right = createBinaryTree();
  }
  
  return p;
  
  
}


void preOrder(BinaryTreeNode *root){
  if(root == NULL) return;
  cout << root->data << " ";
  preOrder(root->left);
  preOrder(root->right);
}



void postOrder(BinaryTreeNode *root){
  if(root == NULL) return;
  postOrder(root->left);
  postOrder(root->right);
  cout << root->data << " ";
}


void inOrder(BinaryTreeNode *root){
  if(root == NULL) return;
  inOrder(root->left);
  cout << root->data << " ";
  inOrder(root->right);
}

int numberBTN(BinaryTreeNode *root){
  if(root == NULL) 
    return 0; 
  return 1 + numberBTN(root->left) + numberBTN(root->right);
}

int numberBTLN(BinaryTreeNode *root){
  if(root == NULL) 
    return 0; 
  if(root->left == NULL && root->right == NULL) 
    return 1; //不同于上一个统计全部节点数目，这回只有叶子节点才统计  
  return  numberBTLN(root->left) + numberBTLN(root->right);
}



/*
  you can also use another method just like:  
  int numberNotBTLN(BinaryTreeNode *root){
    return  numberBTN(root) - numberBTLN(root);
  }
*/
int numberNotBTLN(BinaryTreeNode *root){
  if(root == NULL) 
    return 0; 
  if(root->left != NULL || root->right != NULL) 
    return 1; 
  return  numberBTLN(root->left) + numberBTLN(root->right);
}

int depthBT(BinaryTreeNode *root){
  if(root == NULL)
    return 0;
  int leftHeight = depthBT(root->left);  
  int rightHeight = depthBT(root->right);  
  
  return leftHeight > rightHeight ? leftHeight + 1 : rightHeight + 1;
}

void deleteBT(BinaryTreeNode *root){
  if(root == NULL)
    return;
  deleteBT(root->left);
  deleteBT(root->right);
  free(root);
  root = NULL;  
}

main(){
  BinaryTreeNode *root = NULL;
  root = createBinaryTree();

  cout << "preOrder：";
  preOrder(root);
  cout << endl; 
  
  cout << "inOrder：";
  inOrder(root);
  cout << endl; 
  
  cout << "postOrder：";
  postOrder(root);
  cout << endl; 
  
  cout << "numberBTN：";
  cout << numberBTN(root);
  cout << endl; 
  
  cout << "numberBTLN：";
  cout << numberBTLN(root);
  cout << endl; 
  
  cout << "numberBTLN：";
  cout << numberNotBTLN(root);
  cout << endl; 
  
  cout << "depthBT：";
  cout << depthBT(root);
  cout << endl; 
  
  deleteBT(root);
  
}