C++如何实现二叉树链表
作者:develbai
这篇文章主要介绍了C++如何实现二叉树链表,具有很好的参考价值,希望对大家有所帮助。如有错误或未考虑完全的地方,望不吝赐教
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_H
Tree.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(); } #endif
main.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:
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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脚本之家。