面试题19之二叉树的镜像_MirrorOfBinaryTree.cpp

// MirrorOfBinaryTree.cpp : Defines the entry point for the console application.
//

// 《剑指Offer——名企面试官精讲典型编程题》代码
// 著作权所有者：何海涛

#include "stdafx.h"
#include "Utilities\BinaryTree.h"
#include <stack>

void MirrorRecursively(BinaryTreeNode *pNode)
{
    if((pNode == NULL) || (pNode->m_pLeft == NULL && pNode->m_pRight))
        return;

    BinaryTreeNode *pTemp = pNode->m_pLeft;
    pNode->m_pLeft = pNode->m_pRight;
    pNode->m_pRight = pTemp;
    
    if(pNode->m_pLeft)
        MirrorRecursively(pNode->m_pLeft);  

    if(pNode->m_pRight)
        MirrorRecursively(pNode->m_pRight); 
}

void MirrorIteratively(BinaryTreeNode* pRoot)
{
    if(pRoot == NULL)
        return;

    std::stack<BinaryTreeNode*> stackTreeNode;
    stackTreeNode.push(pRoot);

    while(stackTreeNode.size() > 0)
    {
        BinaryTreeNode *pNode = stackTreeNode.top();
        stackTreeNode.pop();

        BinaryTreeNode *pTemp = pNode->m_pLeft;
        pNode->m_pLeft = pNode->m_pRight;
        pNode->m_pRight = pTemp;

        if(pNode->m_pLeft)
            stackTreeNode.push(pNode->m_pLeft);

        if(pNode->m_pRight)
            stackTreeNode.push(pNode->m_pRight);
    }
}

// ====================测试代码====================
// 测试完全二叉树：除了叶子节点，其他节点都有两个子节点
//            8
//        6      10
//       5 7    9  11
void Test1()
{
    printf("=====Test1 starts:=====\n");
    BinaryTreeNode* pNode8 = CreateBinaryTreeNode(8);
    BinaryTreeNode* pNode6 = CreateBinaryTreeNode(6);
    BinaryTreeNode* pNode10 = CreateBinaryTreeNode(10);
    BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);
    BinaryTreeNode* pNode7 = CreateBinaryTreeNode(7);
    BinaryTreeNode* pNode9 = CreateBinaryTreeNode(9);
    BinaryTreeNode* pNode11 = CreateBinaryTreeNode(11);

    ConnectTreeNodes(pNode8, pNode6, pNode10);
    ConnectTreeNodes(pNode6, pNode5, pNode7);
    ConnectTreeNodes(pNode10, pNode9, pNode11);

    PrintTree(pNode8);

    printf("=====Test1: MirrorRecursively=====\n");
    MirrorRecursively(pNode8);
    PrintTree(pNode8);

    printf("=====Test1: MirrorIteratively=====\n");
    MirrorIteratively(pNode8);
    PrintTree(pNode8);

    DestroyTree(pNode8);
}

// 测试二叉树：出叶子结点之外，左右的结点都有且只有一个左子结点
//            8
//          7   
//        6 
//      5
//    4
void Test2()
{
    printf("=====Test2 starts:=====\n");
    BinaryTreeNode* pNode8 = CreateBinaryTreeNode(8);
    BinaryTreeNode* pNode7 = CreateBinaryTreeNode(7);
    BinaryTreeNode* pNode6 = CreateBinaryTreeNode(6);
    BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);
    BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);

    ConnectTreeNodes(pNode8, pNode7, NULL);
    ConnectTreeNodes(pNode7, pNode6, NULL);
    ConnectTreeNodes(pNode6, pNode5, NULL);
    ConnectTreeNodes(pNode5, pNode4, NULL);

    PrintTree(pNode8);

    printf("=====Test2: MirrorRecursively=====\n");
    MirrorRecursively(pNode8);
    PrintTree(pNode8);

    printf("=====Test2: MirrorIteratively=====\n");
    MirrorIteratively(pNode8);
    PrintTree(pNode8);

    DestroyTree(pNode8);
}

// 测试二叉树：出叶子结点之外，左右的结点都有且只有一个右子结点
//            8
//             7   
//              6 
//               5
//                4
void Test3()
{
    printf("=====Test3 starts:=====\n");
    BinaryTreeNode* pNode8 = CreateBinaryTreeNode(8);
    BinaryTreeNode* pNode7 = CreateBinaryTreeNode(7);
    BinaryTreeNode* pNode6 = CreateBinaryTreeNode(6);
    BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);
    BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);

    ConnectTreeNodes(pNode8, NULL, pNode7);
    ConnectTreeNodes(pNode7, NULL, pNode6);
    ConnectTreeNodes(pNode6, NULL, pNode5);
    ConnectTreeNodes(pNode5, NULL, pNode4);

    PrintTree(pNode8);

    printf("=====Test3: MirrorRecursively=====\n");
    MirrorRecursively(pNode8);
    PrintTree(pNode8);

    printf("=====Test3: MirrorIteratively=====\n");
    MirrorIteratively(pNode8);
    PrintTree(pNode8);

    DestroyTree(pNode8);
}

// 测试空二叉树：根结点为空指针
void Test4()
{
    printf("=====Test4 starts:=====\n");
    BinaryTreeNode* pNode = NULL;

    PrintTree(pNode);

    printf("=====Test4: MirrorRecursively=====\n");
    MirrorRecursively(pNode);
    PrintTree(pNode);

    printf("=====Test4: MirrorIteratively=====\n");
    MirrorIteratively(pNode);
    PrintTree(pNode);
}

// 测试只有一个结点的二叉树
void Test5()
{
    printf("=====Test5 starts:=====\n");
    BinaryTreeNode* pNode8 = CreateBinaryTreeNode(8);

    PrintTree(pNode8);

    printf("=====Test4: MirrorRecursively=====\n");
    MirrorRecursively(pNode8);
    PrintTree(pNode8);

    printf("=====Test4: MirrorIteratively=====\n");
    MirrorIteratively(pNode8);
    PrintTree(pNode8);
}

int _tmain(int argc, _TCHAR* argv[])
{
    Test1();
    Test2();
    Test3();
    Test4();
    Test5();

    return 0;
}