二叉搜索树 与 双向链表 代码(C++)

本文地址: http://blog.csdn.net/caroline_wendy

题目：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, 只能调整数中结点的指针的指向.

方法: 使用中序遍历每一个结点, 并进行连接, 即左子树指前, 右子树指后, 并保存前一个节点.

本程序包含算法原理, 测试程序, 及 输出.

代码:

/*
 * main.cpp
 *
 *  Created on: 2014.6.12
 *      Author: Spike
 */

/*eclipse cdt, gcc 4.8.1*/

#include <iostream>
#include <stack>
#include <queue>

using namespace std;

struct BinaryTreeNode {
	int m_nValue;
	BinaryTreeNode* m_pLeft;
	BinaryTreeNode* m_pRight;
};

void printTree (BinaryTreeNode* tree)
{
	BinaryTreeNode* node = tree;
	std::queue<BinaryTreeNode*> temp1;
	std::queue<BinaryTreeNode*> temp2;

	temp1.push(node);

	while (!temp1.empty())
	{
		node = temp1.front();
		if (node->m_pLeft != NULL) {
			temp2.push(node->m_pLeft);
		}

		if (node->m_pRight != NULL) {
			temp2.push(node->m_pRight);
		}

		temp1.pop();

		std::cout << node->m_nValue  << " ";

		if (temp1.empty())
		{
			std::cout << std::endl;
			temp1 = temp2;
			std::queue<BinaryTreeNode*> empty;
			std::swap(temp2, empty);
		}
	}
}

BinaryTreeNode* buildTree (const std::vector<int>& L)
{
	if (L.empty())
		return nullptr;

	std::queue<BinaryTreeNode*> parentQueue;
	std::queue<BinaryTreeNode*> childQueue;

	BinaryTreeNode* root = new BinaryTreeNode();
	root->m_nValue = L[0];

	parentQueue.push(root);

	std::size_t times = 1;
	while (times < L.size())
	{
		BinaryTreeNode* parent = parentQueue.front();
		parentQueue.pop();

		BinaryTreeNode* lchild = new BinaryTreeNode();
		lchild->m_nValue = L[times];
		lchild->m_pLeft = nullptr;
		lchild->m_pRight = nullptr;
		++times;

		parent->m_pLeft = lchild;
		childQueue.push(lchild);

		if (times == L.size()) break;

		BinaryTreeNode* rchild = new BinaryTreeNode();
		rchild->m_nValue = L[times];
		rchild->m_pLeft = nullptr;
		rchild->m_pRight = nullptr;
		++times;

		parent->m_pRight = rchild;
		childQueue.push(rchild);

		if (parentQueue.empty()) {
			parentQueue = childQueue;
			std::queue<BinaryTreeNode*> empty;
			std::swap(childQueue, empty);
		}
	}

	return root;
}

void printList (BinaryTreeNode* pHeadOfList)
{
	while (pHeadOfList != NULL && pHeadOfList->m_pRight != NULL)
	{
		std::cout << pHeadOfList->m_nValue << " ";
		pHeadOfList = pHeadOfList->m_pRight;
	}

	std::cout << pHeadOfList->m_nValue << " ";
	std::cout << std::endl;

	return;
}

void ConvertNode(BinaryTreeNode* pNode, BinaryTreeNode** pLastNodeInList)
{
	if (pNode == NULL)
		return;

	BinaryTreeNode* pCurrent = pNode;

	if (pCurrent->m_pLeft != NULL)
		ConvertNode(pCurrent->m_pLeft, pLastNodeInList);

	pCurrent->m_pLeft = *pLastNodeInList;
	if (*pLastNodeInList != NULL)
		(*pLastNodeInList)->m_pRight = pCurrent;

	*pLastNodeInList = pCurrent;

	if (pCurrent->m_pRight != NULL)
		ConvertNode(pCurrent->m_pRight, pLastNodeInList);
}

BinaryTreeNode* Convert(BinaryTreeNode* pRootOfTree)
{
	BinaryTreeNode* pLastNodeInList = NULL;
	ConvertNode(pRootOfTree, &pLastNodeInList);

	BinaryTreeNode* pHeadOfList = pLastNodeInList;

	while (pHeadOfList != NULL && pHeadOfList->m_pLeft != NULL)
		pHeadOfList = pHeadOfList->m_pLeft;

	return pHeadOfList;
}

int main (void)
{
	std::vector<int> L = {10, 6, 14, 4, 8, 12, 16};
	BinaryTreeNode* tree = buildTree(L);
	std::cout << "----Tree:----\n";
	printTree(tree);
	BinaryTreeNode* list = Convert(tree);
	std::cout << "----List:----\n";
	printList(list);
	return 0;
}

----Tree:----
10 
6 14 
4 8 12 16 
----List:----
4 6 8 10 12 14 16 

编程算法 - 二叉搜索树 与 双向链表 代码(C++),布布扣,bubuko.com

编程算法 - 二叉搜索树 与 双向链表 代码(C++)