版权声明: https://blog.csdn.net/qq_41880190/article/details/84942867
二叉树的基本实现
#pragma once
#include <iostream>
#include<queue>
#include<stack>
using namespace std;
#include<assert.h>
#if 0
template<class T>
struct BinaryTreeNode
{
T _data;
BinaryTreeNode<T>* _left;
BinaryTreeNode<T>* _right;
BinaryTreeNode(const T& x)
:_left(NULL)
, _right(NULL)
, _data(x)
{}
};
template<class T>
class BinaryTree
{
typedef BinaryTreeNode<T> Node;
public:
BinaryTree()
:_root(NULL)
{}
BinaryTree(T* a, size_t n, const T& invalid)
{
size_t index = 0;
_root = CreateTree(a, n, invalid, index);
}
BinaryTree(const BinaryTree<T>& t);//拷贝构造函数
BinaryTree<T>& operator = (const BinaryTree<T>& t);
~BinaryTree()//析构函数(如何析构)
{
Destroy(_root);
}
void Destroy(Node* root)//成员函数
{
if (root == NULL)
{
return;
}
Destroy(root->_left);
Destroy(root->_right);
delete root;
}
void PrevOrderNonR()//非递归方式前序遍历
{
stack<Node*> s;
Node* cur = _root;
while (cur || !s.empty())
{
while (cur)
{
cout << cur->_data << " ";
s.push(cur);
cur = cur->_left;
}
Node* top = s.pop();
s.pop();
//子问题的方式访问右子树
cur = top->_right;
}
}
void InOrderNonR()
{
stack<Node*> s;
Node* cur = _root;
while (cur || !s.empty())
{
while (cur)
{
s.push(cur);
cur = cur->_left;
}
Node*top = s.pop();
s.pop;
cout << top->_data << " ";
//访问右子树(循环子问题)
cur = top->_right;
}
}
void PostOrderNonR()
{
stack<Node*> s;
Node* cur = _root;
while (cur || !s.empty())
{
while (cur)
{
s.push(cur);//压栈 cur
cur = cur->_left;
}
Node* top = s.pop();
if (top->_right == NULL)//不能先pop掉,右子树还未访问
{
cout << top->_data << " ";
}
cur = top->_right;
}
}
void PrevOrder()
{
_PrevOrder(_root);
cout << endl;
}
void InOrder()
{
_InOrder(_root);
cout << endl;
}
void PostOrder()
{
_PostOrder(_root);
cout << endl;
}
//void LevelOrder();//层次遍历
void LevelOrder()
{
queue<Node*> q;
if (_root)
{
q.push(_root);
}
while (!q.empty())
{
Node* front = q.front();
cout << front->_data << " ";
if (front->_left)
{
q.push(front->_left);
}
if (front->_right)
{
q.push(front->_right);
}
q.pop();
}
cout << endl;
}
//size_t Size();//求结点个数
size_t Size()
{
return _Size(_root);
cout << endl;
}
//size_t LeafSize();//叶子结点个数
size_t LeafSize()
{
return _LeafSize(_root);
cout << endl;
}
//size_t GetKLevel(size_t k);//某层结点个数
/*
size_t GetKLevel(size_t k)
{
assert(k > 0);
}
*/
//size_t Depth();//求二叉树深度
size_t Depth()
{
return _Depth(_root);
}
//Node* Find(const T& x);//找一个数是否存在其中
Node* Find(const T& x)
{
return _Find(_root, x);
}
protected:
Node* _Find(Node* root, const T& x)
{
if (root == NULL)
{
return NULL;
}
if (root->_data == x)
{
return root;
}
Node* ret = _Find(root->_left, x);
if (ret)
{
return ret;
}
return _Find(root->_right, x);
}
void _PrevOrder(Node* root)
{
if (root == NULL)
{
return;
}
cout << root->_data << " ";
_PrevOrder(root->_left);
_PrevOrder(root->_right);
}
void _InOrder(Node* root)
{
if (root == NULL)
{
return;
}
_PrevOrder(root->_left);
cout << root->_data << " ";
_PrevOrder(root->_right);
}
void _PostOrder(Node* root)
{
if (root == NULL)
{
return;
}
_PostOrder(root->_left);
_PostOrder(root->_right);
cout << root->_data << " ";
}
size_t _Size(Node* root)
{
if (root == NULL)
{
return 0;
}
return _Size(root->_left) + _Size(root->_right);
}
size_t _LeafSize(Node* root)
{
if (root == NULL)
{
return 0;
}
if (root->_left == NULL && root->_right == NULL)
{
return 1;
}
return _LeafSize(root->_left) + _LeafSize(root->_right);
}
size_t _GetLevel(Node* root, size_t k)
{
if (root == NULL)
{
return 0;
}
if (k == 1)
{
return 1;
}
return _GetLevel(root->_left, k - 1) + _GetLevel(root->_right, k - 1);
}
size_t _Depth(Node *root)
{
if (root == NULL)
{
return 0;
}
if (root->_left == NULL && root->_right == NULL)
{
return 1;
}
size_t left = _Depth(root->_left);
size_t right = _Depth(root->_right);
return left > right ? left + 1 : right + 1;
}
Node* CreateTree(T* a, size_t n, const T& invalid, size_t& index)
{
//前序建立二叉树
Node* root = NULL;
if (index < n && a[index] != invalid)
{
root = new Node(a[index]);
root->_left = CreateTree(a, n, invalid, ++index);
root->_right = CreateTree(a, n, invalid, ++index);
}
return root;
}
protected:
Node* _root;
};
#endif
struct TreeNode
{
int data;
TreeNode* left;
TreeNode* right;
};
//前序遍历二叉树
void preorder(TreeNode* root)
{
if (root != nullptr)
{
cout << root->data;
preorder(root->left);
preorder(root->right);
}
}
//中序遍历二叉树
void inorder(TreeNode* root)
{
if (root != nullptr)
{
inorder(root->left);
cout << root->data;
inorder(root->right);
}
}
//后续遍历二叉树
void postorder(TreeNode* root)
{
if (root != nullptr)
{
postorder(root->left);
postorder(root->right);
cout << root->data;
}
}
//层序遍历二叉树
//二叉树最大深度
//二叉树最小深度
//二叉树宽度
//二叉树结点个数
//中序遍历的非递归
void inorder(TreeNode* root)
{
stack<TreeNode*> s;
TreeNode* pCur = root;
while (pCur != nullptr || !s.empty())
{
while(pCur != nullptr)
{
s.push(pCur);
pCur = pCur->left;
}
TreeNode* top = s.top();
cout << top->data;
s.pop();
pCur = pCur->right;
}
cout << endl;
}
前序遍历二叉树
void preorder(TreeNode* root)
{
if (root != nullptr)
{
cout << root->data;
preorder(root->left);
preorder(root->right);
}
}
中序遍历二叉树
void inorder(TreeNode* root)
{
if (root != nullptr)
{
inorder(root->left);
cout << root->data;
inorder(root->right);
}
}
后序遍历二叉树
void postorder(TreeNode* root)
{
if (root != nullptr)
{
postorder(root->left);
postorder(root->right);
cout << root->data;
}
}
中序遍历二叉树(非递归)
void inorder(TreeNode* root)
{
stack<TreeNode*> s;
TreeNode* pCur = root;
while (pCur != nullptr || !s.empty())
{
while(pCur != nullptr)
{
s.push(pCur);
pCur = pCur->left;
}
TreeNode* top = s.top();
cout << top->data;
s.pop();
pCur = pCur->right;
}
cout << endl;
}