二叉树遍历

最新推荐文章于 2024-10-21 08:57:50 发布

原创最新推荐文章于 2024-10-21 08:57:50 发布 · 76 阅读

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CC 4.0 BY-SA版权

本文详细介绍了二叉树的构建、遍历方法及树的销毁过程。通过使用C++，展示了如何创建二叉树节点，实现深度优先搜索（DFS）的递归与迭代版本，宽度优先搜索（BFS），并提供了树的打印与销毁函数。通过具体实例演示了这些函数的应用。

// ConsoleApplication2.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include<iostream>
#include <queue>
#include<stack>
using namespace std;

struct Node
{
   int nVal;
   Node *pLeft;
   Node *pRight;

   Node(int val,Node* left=NULL,Node * right=NULL):nVal(val),pLeft(left),pRight(right){}; //构造
};
// 析构
void DestroyTree(Node *pRoot)
{
   if (pRoot==NULL)
       return;

Node* pLeft=pRoot->pLeft;
Node* pRight=pRoot->pRight;

delete pRoot;
pRoot =NULL;

DestroyTree(pLeft);
DestroyTree(pRight);

}

// 用queue实现的BFS
void BFS(Node *pRoot)
{
if (pRoot==NULL)
return;

queue<Node*> Q;

Q.push(pRoot);

while(!Q.empty())
{

Node *node = Q.front();

       cout<<node->nVal<<"->";
       if (node->pLeft!=NULL)
       {
           Q.push(node->pLeft);
       }

       if (node->pRight!=NULL)
       {
           Q.push(node->pRight);
       }

Q.pop();
}

cout<<endl;
}

// DFS的递归实现
void DFS_Recursive(Node* pRoot)
{
if (pRoot==NULL)
return;

cout<<pRoot->nVal<<" ";

if (pRoot->pLeft!=NULL)
DFS_Recursive(pRoot->pLeft);

if (pRoot->pRight!=NULL)
DFS_Recursive(pRoot->pRight);

}

// DFS的迭代实现版本（stack）
void DFS_Iterative(Node* pRoot)
{
if (pRoot==NULL)
return;

stack<Node*> S;
S.push(pRoot);

   while (!S.empty())
   {
       Node *node=S.top();
       cout<<node->nVal<<",";

S.pop();

       if (node->pRight!=NULL)
       {
           S.push(node->pRight);
       }

       if (node->pLeft!=NULL)
       {
           S.push(node->pLeft);
       }

}

// 打印树的信息
void PrintTree(Node* pRoot)
{
if (pRoot==NULL)
return;

cout<<pRoot->nVal<<" ";

   if (pRoot->pLeft!=NULL)
   {
       PrintTree(pRoot->pLeft);
   }

   if (pRoot->pRight!=NULL)
   {
       PrintTree(pRoot->pRight);
   }
}
int _tmain(int argc, _TCHAR* argv[])
{
   Node *node1=new Node(4);
   Node *node2=new Node(5);
   Node *node3=new Node(6);

   Node* node4=new Node(2,node1,node2);
   Node* node5=new Node(3,node3);
   Node* node6=new Node(1,node4,node5);

   Node *node7=new Node(7);
   Node *node8=new Node(8);
   node1->pLeft=node7;
   node1->pRight=node8;

   Node *node10=new Node(10);
   Node *node11=new Node(11);
   node2->pLeft=node10;
   node2->pRight=node11;

   Node* pRoot = node6;
   //PrintTree(pRoot);
   DFS_Recursive(pRoot);

//DFS_Iterative(pRoot);

//   BFS(pRoot);
   DestroyTree(pRoot);
   return 0;
}