输入一颗二叉搜索树，将该二叉搜索树转换成一个排序的双向链表

算法描述：

输入一颗二叉搜索树，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。

算法实现：

/*************************************************************************
	> File Name: main.c
	> Author: cyf
	> Mail: [email protected]
	> Created Time: 2016年05月05日 星期四 16时58分31秒
 ************************************************************************/

#include "Convert.h"

void PrintDoubleLinkedList(struct BinaryTreeNode* pHeadOfList)
{
    struct BinaryTreeNode* pNode = pHeadOfList;

    printf("The nodes from left to right are:\n");
    while(pNode != NULL)
    {
        printf("%d\t", pNode->value);

        if(pNode->right == NULL)
            break;
        pNode = pNode->right;
    }

    printf("\nThe nodes from right to left are:\n");
    while(pNode != NULL)
    {
        printf("%d\t", pNode->value);

        if(pNode->left == NULL)
            break;
        pNode = pNode->left;
    }

    printf("\n");
}

void DestroyList(struct BinaryTreeNode* pHeadOfList)
{
    struct BinaryTreeNode* pNode = pHeadOfList;
    while(pNode != NULL)
    {
        struct BinaryTreeNode* pNext = pNode->right;

        free(pNode);
        pNode = pNext;
    }
}

void Test(char* testName, struct BinaryTreeNode* pRootOfTree)
{
    if(testName != NULL)
        printf("%s begins:\n", testName);

    PrintTree(pRootOfTree);

    struct BinaryTreeNode* pHeadOfList = convert(pRootOfTree);

    PrintDoubleLinkedList(pHeadOfList);
}
void Test1()
{
    struct BinaryTreeNode* pNode10 = CreateBinaryTreeNode(10);
    struct BinaryTreeNode* pNode6 = CreateBinaryTreeNode(6);
    struct BinaryTreeNode* pNode14 = CreateBinaryTreeNode(14);
    struct BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);
    struct BinaryTreeNode* pNode8 = CreateBinaryTreeNode(8);
    struct BinaryTreeNode* pNode12 = CreateBinaryTreeNode(12);
    struct BinaryTreeNode* pNode16 = CreateBinaryTreeNode(16);

    ConnectTreeNodes(pNode10, pNode6, pNode14);
    ConnectTreeNodes(pNode6, pNode4, pNode8);
    ConnectTreeNodes(pNode14, pNode12, pNode16);

    Test("Test1", pNode10);

    DestroyList(pNode4);
}
int main()
{
	Test1();
	return 0;
}

/*************************************************************************
	> File Name: Tree.h
	> Author: cyf
	> Mail: [email protected]
	> Created Time: 2016年04月14日 星期四 20时34分23秒
 ************************************************************************/

#ifndef _TREE_H
#define _TREE_H
#include <stdio.h>
#include <stdlib.h>
struct BinaryTreeNode
{
	int value;
	struct BinaryTreeNode *left;
	struct BinaryTreeNode *right;
};
struct BinaryTreeNode *CreateBinaryTreeNode(int value);
void ConnectTreeNodes(struct BinaryTreeNode *pRoot, struct BinaryTreeNode *pLeft, struct BinaryTreeNode *pRight);
void PrintTreeNode(struct BinaryTreeNode *pNode);
void PrintTree(struct BinaryTreeNode *pRoot);
void DestroyTree(struct BinaryTreeNode *pRoot);

#endif

/*************************************************************************
	> File Name: Tree.c
	> Author: cyf
	> Mail: [email protected]
	> Created Time: 2016年04月14日 星期四 20时38分43秒
 ************************************************************************/

#include "BinaryTree.h"
struct BinaryTreeNode *CreateBinaryTreeNode(int value)
{
	struct BinaryTreeNode *pNode = (struct BinaryTreeNode *)malloc(sizeof(struct BinaryTreeNode));
	pNode->value = value;
	pNode->left = NULL;
	pNode->right = NULL;
	return pNode;
}

void ConnectTreeNodes(struct BinaryTreeNode *pRoot, struct BinaryTreeNode *pLeft, struct BinaryTreeNode *pRight)
{
	if (pRoot != NULL)
	{
		pRoot->left = pLeft;
		pRoot->right = pRight;
	}
}
void PrintTreeNode(struct BinaryTreeNode *pNode)
{
	if (pNode != NULL)
	{
		printf("the value of this node is :%d\n", pNode->value);
		if (pNode->left != NULL)
		{
			printf("the value of left child is %d\n",pNode->left->value);
		}
		else
		{
			printf("the left child is NULL\n");
		}
		if (pNode->right != NULL)
		{
			printf("the value of right child is %d\n",pNode->right->value);
		}
		else
		{
			printf("the right child is NULL\n");
		}
	}
	printf("\n");
}
void PrintTree(struct BinaryTreeNode *pRoot)
{
	PrintTreeNode(pRoot);
	if (pRoot != NULL)
	{
		if (pRoot->left != NULL)
			PrintTree(pRoot->left);
		if (pRoot->right != NULL)
			PrintTree(pRoot->right);
	}
}
void DestroyTree(struct BinaryTreeNode *pRoot)
{
	if (pRoot != NULL)
	{
		struct BinaryTreeNode *pLeft = pRoot->left;
		struct BinaryTreeNode *pRight = pRoot->right;

		free(pRoot);
		//pRoot == NULL;
		DestroyTree(pLeft);
		DestroyTree(pRight);
	}
}

/*************************************************************************
	> File Name: Convert.h
	> Author: cyf
	> Mail: [email protected]
	> Created Time: 2016年05月05日 星期四 16时38分25秒
 ************************************************************************/

#ifndef _CONVERT_H
#define _CONVERT_H
#include <stdio.h>
#include <stdlib.h>
#include "BinaryTree.h"
struct BinaryTreeNode* convert(struct BinaryTreeNode *pRoot);
void convertTree(struct BinaryTreeNode *pRoot, struct BinaryTreeNode **pLastNodeInList);


#endif

/*************************************************************************
	> File Name: Convert.c
	> Author: cyf
	> Mail: [email protected]
	> Created Time: 2016年05月05日 星期四 16时40分37秒
 ************************************************************************/

#include "Convert.h"

struct BinaryTreeNode* convert(struct BinaryTreeNode *pRoot)
{
	struct BinaryTreeNode *pLastNodeInList = NULL;
	convertTree(pRoot, &pLastNodeInList);
	struct BinaryTreeNode *pHeadList = pLastNodeInList;
	while (pHeadList != NULL && pHeadList->left != NULL)
		pHeadList = pHeadList->left;

	return pHeadList;
}

void convertTree(struct BinaryTreeNode *pRoot, struct BinaryTreeNode **pLastNodeInList)
{
	if (pRoot == NULL)
		return ;
	struct BinaryTreeNode *pCurrent = pRoot;

	if (pCurrent->left != NULL)
		convertTree(pCurrent->left, pLastNodeInList);
	pCurrent->left = *pLastNodeInList;
	if (*pLastNodeInList != NULL)
		(*pLastNodeInList)->right = pCurrent;
	*pLastNodeInList = pCurrent;
	if (pCurrent->right != NULL)
		convertTree(pCurrent->right, pLastNodeInList);
}

CC = gcc
CFLAGS = -g -O2 -Wall

%.o:%.c
	$(CC) -o $@ -c $(CFLAGS) $<

main:main.o Convert.o BinaryTree.o
	$(CC) main.o Convert.o BinaryTree.o -o main $(CFLAGS)

clean:
	rm -rf *.o main