二叉树转双向链表+BFS+中序遍历

/******************************
作者：cncoderalex
博客：http://blog.youkuaiyun.com/cncoderalex
*******************************/


#include"Test.h"
#include<iostream>
#include<queue>

using namespace std;

struct Node
{
	int Data;
	Node *pLeft;
	Node *pRight;
};

Node *CreateTree(int Ary[], int nCount)
{
	if (!Ary || nCount <= 0)
		return NULL;

	int index = 0;
	Node *pRoot = new Node();
	pRoot->pLeft = pRoot->pRight = NULL;
	pRoot->Data = Ary[index++];

	queue<Node *> que;
	que.push(pRoot);

	while (!que.empty())
	{
		Node *pParent = que.front();
		que.pop();

		if (index < nCount)
		{
			Node *pTemp = new Node();
			pTemp->pLeft = pTemp->pRight = NULL;
			pTemp->Data = Ary[index++];
			pParent->pLeft = pTemp;

			que.push(pTemp);
		}
		else
		{
			break;
		}

		if (index < nCount)
		{
			Node *pTemp = new Node();
			pTemp->pLeft = pTemp->pRight = NULL;
			pTemp->Data = Ary[index++];
			pParent->pRight = pTemp;

			que.push(pTemp);
		}
		else
		{
			break;
		}
	}

	return pRoot;
}

void DestroyTree(Node *&pRoot)
{
	if (!pRoot)
		return;

	DestroyTree(pRoot->pLeft);
	DestroyTree(pRoot->pRight);

	delete pRoot;
	pRoot = NULL;
}

void BFS(Node *pRoot)
{
	if (!pRoot)
		return;

	queue<Node *> que;
	que.push(pRoot);

	while (!que.empty())
	{
		Node *pTemp = que.front();
		que.pop();

		printf("%d ", pTemp->Data);

		if (pTemp->pLeft)
		{
			que.push(pTemp->pLeft);
		}

		if (pTemp->pRight)
		{
			que.push(pTemp->pRight);
		}
	}

	printf("\n");
}

void InOrderTraverse(Node *pRoot)
{
	if (!pRoot)
		return;

	InOrderTraverse(pRoot->pLeft);
	printf("%d ", pRoot->Data);
	InOrderTraverse(pRoot->pRight);
}

void Convert2DList(Node *pRoot, Node *&pLeft, Node *&pRight)
{
	if (!pRoot)
	{
		pLeft = pRoot = NULL;
		return;
	}

	if (!pRoot->pLeft && !pRoot->pRight)
	{
		pLeft = pRight = pRoot;
		return;
	}

	Node *pLeftRight = NULL;
	Node *pRightLeft = NULL;

	if (pRoot->pLeft)
	{
		Convert2DList(pRoot->pLeft, pLeft, pLeftRight);

		pLeftRight->pRight = pRoot;
		pRoot->pLeft = pLeftRight;
	}
	else
	{
		pLeft = pRoot;
		pRoot->pLeft = NULL;
	}

	if (pRoot->pRight)
	{
		Convert2DList(pRoot->pRight, pRightLeft, pRight);

		pRightLeft->pLeft = pRoot;
		pRoot->pRight = pRightLeft;
	}
	else
	{
		pRight = pRoot;
		pRoot->pRight = NULL;
	}

}

void PrintDList(Node *pRoot)
{
	if (!pRoot)
		return;

	printf("%d ", pRoot->Data);
	while (pRoot->pRight)
	{
		pRoot = pRoot->pRight;
		printf("%d ", pRoot->Data);
	}

	printf("\n");

}

void DestroyDList(Node *pRoot)
{
	if (!pRoot)
		return;

	while (pRoot)
	{
		Node *pTemp = pRoot;
		pRoot = pRoot->pRight;

		delete pTemp;
	}
}


int main()
{
	printf("http://blog.youkuaiyun.com/cncoderalex");
	printf("\n");

	_CrtSetDbgFlag(_CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF);

	Node *pRoot = NULL;
	int AryTree[] = { 1, 2, 3, 4, 5, 6, 7, 8 };

	pRoot = CreateTree(AryTree, sizeof(AryTree) / sizeof(int));
	InOrderTraverse(pRoot);
	printf("\n");
	Node *pLeft = NULL, *pRight = NULL;
	Convert2DList(pRoot, pLeft, pRight);
	PrintDList(pLeft);
	DestroyDList(pLeft);

	system("pause");
	return 0;
}