zoukankan      html  css  js  c++  java
  • 《剑指offer》第三十六题(二叉搜索树与双向链表)

    // 面试题36:二叉搜索树与双向链表
    // 题目:输入一棵二叉搜索树,将该二叉搜索树转换成一个排序的双向链表。要求
    // 不能创建任何新的结点,只能调整树中结点指针的指向。
    
    #include <iostream>
    #include "BinaryTree.h"
    //这个程序看的我真的是头大如牛
    
    void ConvertNode(BinaryTreeNode* pNode, BinaryTreeNode** pLastNodeInList);
    
    BinaryTreeNode* Convert(BinaryTreeNode* pRootOfTree)
    {
        BinaryTreeNode *pLastNodeInList = nullptr;
        ConvertNode(pRootOfTree, &pLastNodeInList);//看这个核心代码
    
        // pLastNodeInList指向双向链表的尾结点,我们需要返回头结点
        BinaryTreeNode *pHeadOfList = pLastNodeInList;
        while (pHeadOfList != nullptr && pHeadOfList->m_pLeft != nullptr)
            pHeadOfList = pHeadOfList->m_pLeft;
    
        return pHeadOfList;
    }
    
    void ConvertNode(BinaryTreeNode* pNode, BinaryTreeNode** pLastNodeInList)
    {
        if (pNode == nullptr)
            return;
    
        BinaryTreeNode *pCurrent = pNode;
    
        if (pCurrent->m_pLeft != nullptr)//找到当前树的最小节点
            ConvertNode(pCurrent->m_pLeft, pLastNodeInList);
    
        pCurrent->m_pLeft = *pLastNodeInList;//当前树根的左孩子,指向左孩子子树的最小值
        if (*pLastNodeInList != nullptr)
            (*pLastNodeInList)->m_pRight = pCurrent;//把左孩子的m_pRight指向当前树根
    
        *pLastNodeInList = pCurrent;
    
        if (pCurrent->m_pRight != nullptr)//继续把右面调整好
            ConvertNode(pCurrent->m_pRight, pLastNodeInList);
    }
    
    // ====================测试代码====================
    void PrintDoubleLinkedList(BinaryTreeNode* pHeadOfList)
    {
        BinaryTreeNode* pNode = pHeadOfList;
    
        printf("The nodes from left to right are:
    ");
        while (pNode != nullptr)
        {
            printf("%d	", pNode->m_nValue);
    
            if (pNode->m_pRight == nullptr)
                break;
            pNode = pNode->m_pRight;
        }
    
        printf("
    The nodes from right to left are:
    ");
        while (pNode != nullptr)
        {
            printf("%d	", pNode->m_nValue);
    
            if (pNode->m_pLeft == nullptr)
                break;
            pNode = pNode->m_pLeft;
        }
    
        printf("
    ");
    }
    
    void DestroyList(BinaryTreeNode* pHeadOfList)
    {
        BinaryTreeNode* pNode = pHeadOfList;
        while (pNode != nullptr)
        {
            BinaryTreeNode* pNext = pNode->m_pRight;
    
            delete pNode;
            pNode = pNext;
        }
    }
    
    void Test(const char* testName, BinaryTreeNode* pRootOfTree)
    {
        if (testName != nullptr)
            printf("%s begins:
    ", testName);
    
        PrintTree(pRootOfTree);
    
        BinaryTreeNode* pHeadOfList = Convert(pRootOfTree);
    
        PrintDoubleLinkedList(pHeadOfList);
    }
    
    //            10
    //         /      
    //        6        14
    //       /        /
    //      4  8     12  16
    void Test1()
    {
        BinaryTreeNode* pNode10 = CreateBinaryTreeNode(10);
        BinaryTreeNode* pNode6 = CreateBinaryTreeNode(6);
        BinaryTreeNode* pNode14 = CreateBinaryTreeNode(14);
        BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);
        BinaryTreeNode* pNode8 = CreateBinaryTreeNode(8);
        BinaryTreeNode* pNode12 = CreateBinaryTreeNode(12);
        BinaryTreeNode* pNode16 = CreateBinaryTreeNode(16);
    
        ConnectTreeNodes(pNode10, pNode6, pNode14);
        ConnectTreeNodes(pNode6, pNode4, pNode8);
        ConnectTreeNodes(pNode14, pNode12, pNode16);
    
        Test("Test1", pNode10);
    
        DestroyList(pNode4);
    }
    
    //               5
    //              /
    //             4
    //            /
    //           3
    //          /
    //         2
    //        /
    //       1
    void Test2()
    {
        BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);
        BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);
        BinaryTreeNode* pNode3 = CreateBinaryTreeNode(3);
        BinaryTreeNode* pNode2 = CreateBinaryTreeNode(2);
        BinaryTreeNode* pNode1 = CreateBinaryTreeNode(1);
    
        ConnectTreeNodes(pNode5, pNode4, nullptr);
        ConnectTreeNodes(pNode4, pNode3, nullptr);
        ConnectTreeNodes(pNode3, pNode2, nullptr);
        ConnectTreeNodes(pNode2, pNode1, nullptr);
    
        Test("Test2", pNode5);
    
        DestroyList(pNode1);
    }
    
    // 1
    //  
    //   2
    //    
    //     3
    //      
    //       4
    //        
    //         5
    void Test3()
    {
        BinaryTreeNode* pNode1 = CreateBinaryTreeNode(1);
        BinaryTreeNode* pNode2 = CreateBinaryTreeNode(2);
        BinaryTreeNode* pNode3 = CreateBinaryTreeNode(3);
        BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);
        BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);
    
        ConnectTreeNodes(pNode1, nullptr, pNode2);
        ConnectTreeNodes(pNode2, nullptr, pNode3);
        ConnectTreeNodes(pNode3, nullptr, pNode4);
        ConnectTreeNodes(pNode4, nullptr, pNode5);
    
        Test("Test3", pNode1);
    
        DestroyList(pNode1);
    }
    
    // 树中只有1个结点
    void Test4()
    {
        BinaryTreeNode* pNode1 = CreateBinaryTreeNode(1);
        Test("Test4", pNode1);
    
        DestroyList(pNode1);
    }
    
    // 树中没有结点
    void Test5()
    {
        Test("Test5", nullptr);
    }
    
    int main(int argc, char* argv[])
    {
        Test1();
        Test2();
        Test3();
        Test4();
        Test5();
        system("pause");
        return 0;
    }
  • 相关阅读:
    关于Android的布局
    一个新的开端
    Flux的基础概念和实战入门
    在Redux中使用插件createAction之后
    学习
    Object.assign() 对象的扩展
    Redux 中的CombineReducer的函数详解
    React组件的防呆机制(propTypes)
    css的新特性 calc () 使用
    shim和polyfill有什么区别
  • 原文地址:https://www.cnblogs.com/CJT-blog/p/10498621.html
Copyright © 2011-2022 走看看