C++二叉树链表
Node.h
#ifndef NODE_H
#define NODE_H
#include <iostream>
using namespace std;
class Node
{
public:
Node();
~Node();
Node *SearchNode(int nodeIndex);
void DeleteNode();
void PreordeTraverse();
void InorderTraverse();
void PostorderTraverse();
int index;
int data;
Node *pLChild;
Node *pRChild;
Node *pParent;
private:
};
Node::Node()
{
index = 0;
data = 0;
pLChild = NULL;
pRChild = NULL;
pParent = NULL;
}
Node::~Node()
{
}
Node *Node::SearchNode(int nodeIndex)
{
Node *temp = NULL;
if (this->index == nodeIndex)
{
return this;
}
if (this->pLChild != NULL)
{
if (this->pLChild->index == nodeIndex)
{
return this->pLChild;
}
else
{
temp = this->pLChild->SearchNode(nodeIndex);
if (temp != NULL)
{
return temp;
}
}
}
if (this->pRChild != NULL)
{
if (this->pRChild->index == nodeIndex)
{
return this->pRChild;
}
else
{
this->pRChild->SearchNode(nodeIndex);
if (temp != NULL)
{
return temp;
}
}
}
return NULL;
}
void Node::DeleteNode()
{
if (this->pLChild != NULL)
{
this->pLChild->DeleteNode();
}
if (this->pRChild != NULL)
{
this->pRChild->DeleteNode();
}
if (this->pParent != NULL)
{
if (this->pParent->pLChild == this)
{
this->pParent->pLChild = NULL;
}
if (this->pParent->pRChild == this)
{
this->pParent->pRChild = NULL;
}
}
delete this;
}
void Node::PreordeTraverse()
{
cout << this->index << " " << this->data << endl;
if (this->pLChild != NULL)
{
this->pLChild->PreordeTraverse();
}
if (this->pRChild != NULL)
{
this->pRChild->PreordeTraverse();
}
}
void Node::InorderTraverse()
{
if (this->pLChild != NULL)
{
this->pLChild->InorderTraverse();
}
cout << this->index << " " << this->data << endl;
if (this->pRChild != NULL)
{
this->pRChild->InorderTraverse();
}
}
void Node::PostorderTraverse()
{
if (this->pLChild != NULL)
{
this->pLChild->PostorderTraverse();
}
if (this->pRChild != NULL)
{
this->pRChild->PostorderTraverse();
}
cout << this->index << " " << this->data << endl;
}
#endif // !NODE_HTree.h
#ifndef TREE_H
#define TREE_H
#include "Node.h"
#include <iostream>
using namespace std;
class Tree
{
public:
Tree(); //创建树
~Tree(); //销毁树
Node *SearchNode(int nodeIndex); //根据索引寻找节点
bool AddNode(int nodeIndex, int direction, Node *pNode); //添加节点
bool DeleteNode(int nodeIndex, Node *pNode); //删除节点
void PreordeTraverse(); //前序遍历
void InorderTraverse(); //中序遍历
void PostorderTraverse(); //后序遍历
private:
Node *m_pRoot;
};
Tree::Tree()
{
m_pRoot = new Node();
}
Tree::~Tree()
{
m_pRoot->DeleteNode();
}
Node *Tree::SearchNode(int nodeIndex)
{
return m_pRoot->SearchNode(nodeIndex);
}
bool Tree::AddNode(int nodeIndex, int direction, Node *pNode)
{
Node *temp = SearchNode(nodeIndex);
if (temp != NULL)
{
Node *currentNode = new Node;
if (currentNode == NULL)
{
return false;
}
currentNode->index = pNode->index;
currentNode->data = pNode->data;
currentNode->pParent = temp;
if (direction == 0)
{
temp->pLChild = currentNode;
}
if (direction == 1)
{
temp->pRChild = currentNode;
}
return true;
}
return false;
}
bool Tree::DeleteNode(int nodeIndex, Node *pNode)
{
Node *temp = SearchNode(nodeIndex);
if (temp == NULL)
{
return false;
}
if (pNode != NULL)
{
pNode->data = temp->data;
}
temp->DeleteNode();
return true;
}
void Tree::PreordeTraverse()
{
m_pRoot->PreordeTraverse();
}
void Tree::InorderTraverse()
{
m_pRoot->InorderTraverse();
}
void Tree::PostorderTraverse()
{
m_pRoot->PostorderTraverse();
}
#endifmain.cpp
#include "Tree.h"
#include "Node.h"
int main()
{
Tree *pTree = new Tree;
Node *e1 = new Node;
e1->index = 1;
e1->data = 1;
Node *e2 = new Node;
e2->index = 2;
e2->data = 2;
Node *e3 = new Node;
e3->index = 3;
e3->data = 3;
Node *e4 = new Node;
e4->index = 4;
e4->data = 4;
Node *e5 = new Node;
e5->index = 5;
e5->data = 5;
Node *e6 = new Node;
e6->index = 6;
e6->data = 6;
Node *e7 = new Node;
e7->index = 7;
e7->data = 7;
Node *e8 = new Node;
e8->index = 8;
e8->data = 8;
pTree->AddNode(0, 0, e1);
pTree->AddNode(0, 1, e2);
pTree->AddNode(1, 0, e3);
pTree->AddNode(1, 1, e4);
pTree->AddNode(2, 0, e5);
pTree->AddNode(2, 1, e6);
pTree->AddNode(3, 0, e7);
pTree->AddNode(4, 1, e8);
//pTree->DeleteNode(2, NULL);
pTree->PreordeTraverse();
cout << endl;
pTree->InorderTraverse();
cout << endl;
pTree->PostorderTraverse();
delete pTree;
system("pause");
return 0;
}C++二叉树转链表
给定一个二叉树，将该二叉树就地(in-place)转换为单链表。单链表中节点顺序为二叉树前序遍历顺序。
如果不要求就地转链表，可以借助于一个vector将二叉树转为链表。
代码如下：
#include<vector>
struct TreeNode
{
int val;
TreeNode* left;
TreeNode* right;
TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};
class Solution
{
public:
Solution() {};
~Solution() {};
void flatten(TreeNode * root)
{
std::vector<TreeNode*> node_vec;
preorder(root,node_vec);
for (int i = 1; i < node_vec.size(); i++)
{
node_vec[i - 1]->left = NULL;
node_vec[i - 1]->right = node_vec[i];
}
}
private:
void preorder(TreeNode* node, std::vector<TreeNode*>& node_vec)
{
if (!node)
{
return;
}
node_vec.push_back(node);
preorder(node->left, node_vec);
preorder(node->right, node_vec);
}
};
int main()
{
TreeNode a(1);
TreeNode b(2);
TreeNode c(5);
TreeNode d(3);
TreeNode e(4);
TreeNode f(6);
a.left = &b;
a.right = &c;
b.left = &d;
b.right = &e;
c.right = &f;
Solution solve;
solve.flatten(&a);
TreeNode* head = &a;
while (head)
{
if (head->left)
{
printf("Error\n");
}
printf("[%d]", head->val);
head = head->right;
}
printf("\n");
return 0;
}运行结果：
[1][2][3][4][5][6]
因为要求就地将二叉树转为链表，因此不能借助于vector。
#include<vector>
struct TreeNode
{
int val;
TreeNode* left;
TreeNode* right;
TreeNode(int x) :val(x), left(NULL), right(NULL) {}
};
class Solution
{
public:
Solution() {};
~Solution() {};
void flatten(TreeNode* root)
{
TreeNode* last = NULL;
preorder(root,last);
}
private:
void preorder(TreeNode* node, TreeNode* & last)
{
if (!node)
{
return;
}
if (!node->left&&!node->right)
{
last = node;
return;
}
TreeNode* left = node->left;
TreeNode* right = node->right;
TreeNode* left_last =NULL;
TreeNode* right_last = NULL;
if (left)
{
preorder(left, left_last);
node->left = NULL;
node->right = left;
last = left_last;
}
if (right)
{
preorder(right, right_last);
if (left)
{
left_last->right = right;
}
last = right_last;
}
}
};
int main()
{
TreeNode a(1);
TreeNode b(2);
TreeNode c(5);
TreeNode d(3);
TreeNode e(4);
TreeNode f(6);
a.left = &b;
a.right = &c;
b.left = &d;
b.right = &e;
c.right = &f;
Solution solve;
solve.flatten(&a);
TreeNode* head = &a;
while (head)
{
if (head->left)
{
printf("Error\n");
}
printf("[%d]", head->val);
head = head->right;
}
printf("\n");
return 0;
}运行结果为：
[1][2][3][4][5][6]
以上为个人经验，希望能给大家一个参考，也希望大家多多支持编程网。
