#include <iostream>
using namespace std;
class Node
{
public:
  Node* left;
  Node* right;
  int data;
  Node();
  Node(int d);
};
class BinaryTree
{
public:
  Node* root;
  //创建树
  void create_tree(Node** node, int len);
  //求最小值
  int min(int a, int b);
  //寻找第二小值
  int search_second_small();
  BinaryTree();
};
int main()
{
  int arr[10] = {89, 123, 7, 9, 2, 5, 25, 8, 43, 23};

//叶子节点
  Node** node =new Node*[10];
  for(int i =0; i <10; i++)
    node[i] =new Node(arr[i]);
  BinaryTree* bi_tree =new BinaryTree();
  bi_tree->create_tree(node, 10);
  cout<<bi_tree->root->data<<endl;
  cout<<bi_tree->search_second_small()<<endl;
  return 0;
}
Node::Node()
{
  left = right = NULL;
}
Node::Node(int d)
{
  data = d;
  left = right = NULL;
}
void BinaryTree::create_tree(Node** node, int len)
{
  //len == 2时，就剩下两个元素进行比较了，得到最后一个元素为root节点，即最小值节点
  if(len ==2)
  {
    root->left = node[0];
    root->right = node[1];
    root->data = min(node[0]->data, node[1]->data);
  }
  else
  {
    int new_len = (len%2) ? (len/2+1) : len/2;
    Node** new_node =new Node*[new_len];
    //new_node元素个数为奇数
    if(len%2)
    {
      for(int i =0; i < new_len -1; i++)
      {
        //构建父亲节点
        new_node[i] =new Node(min(node[2*i]->data, node[2*i+1]->data));
        new_node[i]->left = node[2*i];
        new_node[i]->right = node[2*i+1];
      }
      new_node[new_len -1] = node[len -1];
    }
    //new_node元素个数为偶数
    else
    {
      for(int i =0; i < new_len; i++)
      {
        //构建父亲节点
        new_node[i] =new Node(min(node[2*i]->data, node[2*i+1]->data));
        new_node[i]->left = node[2*i];
        new_node[i]->right = node[2*i+1];
      }
    }
    create_tree(new_node, new_len);
    delete[] new_node;
  }
}
int BinaryTree::min(int a, int b)
{
  return a < b ? a : b;
}
int BinaryTree::search_second_small()
{
  int second =1000000;
  Node* p = root;
  while(p->left != NULL && p->right != NULL)
  {
    if(p->data == p->left->data && second > p->right->data)
    {
      second = p->right->data;
      p = p->left;
    }
    else if(p->data == p->right->data && second > p->left->data)
    {
      second = p->left->data;
      p = p->right;
    }
    else
      return second;
  }
  return second;
}
BinaryTree::BinaryTree()
{
  root = new Node();
}