JZ-C-23

剑指offer第二十三题：从上往下打印二叉树

//============================================================================
// Name        : JZ-C-23.cpp
// Author      : Laughing_Lz
// Version     :
// Copyright   : All Right Reserved
// Description : 从上往下打印二叉树
//============================================================================

#include <iostream>
#include <stdio.h>
#include <deque>
#include "BinaryTree.h"
using namespace std;
/**
 *层次遍历二叉树，相当于广度优先遍历,都需要利用队列
 */
void PrintFromTopToBottom(BinaryTreeNode* pTreeRoot){
    if(pTreeRoot == NULL){
        return;
    }
    std::deque<BinaryTreeNode*> dequeTreeNode;//这是一个两端都可以进出的队列★
    dequeTreeNode.push_back(pTreeRoot);//从后进队列
    while(!dequeTreeNode.empty()){
        BinaryTreeNode* Node = dequeTreeNode.front();//从前出队列
        dequeTreeNode.pop_front();
        cout<<Node->m_nValue<<endl;//打印
        if(Node->m_pLeft){
            dequeTreeNode.push_back(Node->m_pLeft);
        }
        if(Node->m_pRight){
            dequeTreeNode.push_back(Node->m_pRight);
        }
    }
}

// ====================测试代码====================
void Test(char* testName, BinaryTreeNode* pRoot)
{
    if(testName != NULL)
        printf("%s begins: 
", testName);

    PrintTree(pRoot);

    printf("The nodes from top to bottom, from left to right are: 
");
    PrintFromTopToBottom(pRoot);

    printf("

");
}

//            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);

    DestroyTree(pNode10);
}

//               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, NULL);
    ConnectTreeNodes(pNode4, pNode3, NULL);
    ConnectTreeNodes(pNode3, pNode2, NULL);
    ConnectTreeNodes(pNode2, pNode1, NULL);

    Test("Test2", pNode5);

    DestroyTree(pNode5);
}

// 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, NULL, pNode2);
    ConnectTreeNodes(pNode2, NULL, pNode3);
    ConnectTreeNodes(pNode3, NULL, pNode4);
    ConnectTreeNodes(pNode4, NULL, pNode5);

    Test("Test3", pNode1);

    DestroyTree(pNode1);
}

// 树中只有1个结点
void Test4()
{
    BinaryTreeNode* pNode1 = CreateBinaryTreeNode(1);
    Test("Test4", pNode1);

    DestroyTree(pNode1);
}

// 树中没有结点
void Test5()
{
    Test("Test5", NULL);
}

int main(int argc, char** argv)
{
    Test1();
    Test2();
    Test3();
    Test4();
    Test5();

   return 0;
}