面试题61之按之字形顺序打印二叉树_PrintTreesInzigzag.cpp

/* 
 * Question Description:
 * (Question 59 in <Coding Intervies>) How do you print a binary tree by level in zigzag order, 
 * each level in a line? That is to say, nodes on the first level are printed from left to right, 
 * nodes on the second level are printed from right to left, nodes on the third level are printed 
 * from left to right again, and so on.  
*/

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

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

    std::stack<BinaryTreeNode*> levels[2];
    int current = 0;
    int next = 1;

    levels[current].push(pRoot);
    while(!levels[0].empty() || !levels[1].empty())
    {
        BinaryTreeNode* pNode = levels[current].top();
        levels[current].pop();

        printf("%d ", pNode->m_nValue);

        if(current == 0)
        {
            if(pNode->m_pLeft != NULL)
                levels[next].push(pNode->m_pLeft);
            if(pNode->m_pRight != NULL)
                levels[next].push(pNode->m_pRight);
        }
        else
        {
            if(pNode->m_pRight != NULL)
                levels[next].push(pNode->m_pRight);
            if(pNode->m_pLeft != NULL)
                levels[next].push(pNode->m_pLeft);
        }

        if(levels[current].empty())
        {
            printf("\n");
            current = 1 - current;
            next = 1 - next;
        }
    }
}

//            8
//        6      10
//       5 7    9  11
void Test1()
{
    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);

    printf("====Test1 Begins: ====\n");
    printf("Expected Result is:\n");
    printf("8 \n");
    printf("10 6 \n");
    printf("5 7 9 11 \n\n");

    printf("Actual Result is: \n");
    Print(pNode8);
    printf("\n");

    DestroyTree(pNode8);
}

//            5
//          4
//        3
//      2
void Test2()
{
    BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);
    BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);
    BinaryTreeNode* pNode3 = CreateBinaryTreeNode(3);
    BinaryTreeNode* pNode2 = CreateBinaryTreeNode(2);

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

    printf("====Test2 Begins: ====\n");
    printf("Expected Result is:\n");
    printf("5 \n");
    printf("4 \n");
    printf("3 \n");
    printf("2 \n\n");

    printf("Actual Result is: \n");
    Print(pNode5);
    printf("\n");

    DestroyTree(pNode5);
}

//        5
//         4
//          3
//           2
void Test3()
{
    BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);
    BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);
    BinaryTreeNode* pNode3 = CreateBinaryTreeNode(3);
    BinaryTreeNode* pNode2 = CreateBinaryTreeNode(2);

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

    printf("====Test3 Begins: ====\n");
    printf("Expected Result is:\n");
    printf("5 \n");
    printf("4 \n");
    printf("3 \n");
    printf("2 \n\n");

    printf("Actual Result is: \n");
    Print(pNode5);
    printf("\n");

    DestroyTree(pNode5);
}

void Test4()
{
    BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);

    printf("====Test4 Begins: ====\n");
    printf("Expected Result is:\n");
    printf("5 \n\n");

    printf("Actual Result is: \n");
    Print(pNode5);
    printf("\n");

    DestroyTree(pNode5);
}

void Test5()
{
    printf("====Test5 Begins: ====\n");
    printf("Expected Result is:\n");

    printf("Actual Result is: \n");
    Print(NULL);
    printf("\n");
}

//        100
//        /
//       50   
//         \
//         150
void Test6()
{
    BinaryTreeNode* pNode100 = CreateBinaryTreeNode(100);
    BinaryTreeNode* pNode50 = CreateBinaryTreeNode(50);
    BinaryTreeNode* pNode150 = CreateBinaryTreeNode(150);

    ConnectTreeNodes(pNode100, pNode50, NULL);
    ConnectTreeNodes(pNode50, NULL, pNode150);

    printf("====Test6 Begins: ====\n");
    printf("Expected Result is:\n");
    printf("100 \n");
    printf("50 \n");
    printf("150 \n\n");

    printf("Actual Result is: \n");
    Print(pNode100);
    printf("\n");
}

//                8
//        4              12
//     2     6       10      14
//   1  3  5  7     9 11   13  15
void Test7()
{
    BinaryTreeNode* pNode8 = CreateBinaryTreeNode(8);
    BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);
    BinaryTreeNode* pNode12 = CreateBinaryTreeNode(12);
    BinaryTreeNode* pNode2 = CreateBinaryTreeNode(2);
    BinaryTreeNode* pNode6 = CreateBinaryTreeNode(6);
    BinaryTreeNode* pNode10 = CreateBinaryTreeNode(10);
    BinaryTreeNode* pNode14 = CreateBinaryTreeNode(14);
    BinaryTreeNode* pNode1 = CreateBinaryTreeNode(1);
    BinaryTreeNode* pNode3 = CreateBinaryTreeNode(3);
    BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);
    BinaryTreeNode* pNode7 = CreateBinaryTreeNode(7);
    BinaryTreeNode* pNode9 = CreateBinaryTreeNode(9);
    BinaryTreeNode* pNode11 = CreateBinaryTreeNode(11);
    BinaryTreeNode* pNode13 = CreateBinaryTreeNode(13);
    BinaryTreeNode* pNode15 = CreateBinaryTreeNode(15);

    ConnectTreeNodes(pNode8, pNode4, pNode12);
    ConnectTreeNodes(pNode4, pNode2, pNode6);
    ConnectTreeNodes(pNode12, pNode10, pNode14);
    ConnectTreeNodes(pNode2, pNode1, pNode3);
    ConnectTreeNodes(pNode6, pNode5, pNode7);
    ConnectTreeNodes(pNode10, pNode9, pNode11);
    ConnectTreeNodes(pNode14, pNode13, pNode15);

    printf("====Test7 Begins: ====\n");
    printf("Expected Result is:\n");
    printf("8 \n");
    printf("12 4 \n");
    printf("2 6 10 14 \n");
    printf("15 13 11 9 7 5 3 1 \n\n");

    printf("Actual Result is: \n");
    Print(pNode8);
    printf("\n");

    DestroyTree(pNode8);
}

int main(int argc, char* argv[])
{
    Test1();
    Test2();
    Test3();
    Test4();
    Test5();
    Test6();
    Test7();

	return 0;
}