二叉树的遍历

Sat, 08 Sep 2012 17:01:31 +0800

参考 http://blog.csdn.net/acdnjjjdjkdckjj/article/details/6237970 写了二叉树的遍历，（基本上就是照抄的，囧），抄的时候感慨，stl 真是个好东西啊，另外，在三种次序遍历的实现上，递归的精巧发挥的淋漓尽致啊，还有就是非递归的遍历，设计真的好巧妙

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

using namespace std;

class Tree
{
public:
	char data;
	Tree *left;
	Tree *right;
	void create(Tree *&node);
	void preOrderVisit(Tree *node);
	void inOrderVisit(Tree *node);
	void lastOrderVisit(Tree *node);
	void levelOrderVisit(Tree *node);
	void notRecursionPreOrderVisit(Tree *node);
	void notRecursionInorderVisit(Tree *node);
	void notRecursionLastOrderVisit(Tree *node);
};

void Tree::create(Tree *&node)
{
	char ch;
	cin>>ch;
	if (ch == '0')
	{
		node = NULL;
	}
	else
	{
		node = new Tree();
		node->data = ch;
		create(node->left);
		create(node->right);
	}
}

void Tree::preOrderVisit(Tree *node)
{
	if (node)
	{
		cout<<node->data<<' ';
		preOrderVisit(node->left);
		preOrderVisit(node->right);
	}
}

void Tree::inOrderVisit(Tree *node)
{
	if (node)
	{
		inOrderVisit(node->left);
		cout<<node->data<<' ';
		inOrderVisit(node->right);
	}
}

void Tree::lastOrderVisit(Tree *node)
{
	if (node)
	{
		lastOrderVisit(node->left);
		lastOrderVisit(node->right);
		cout<<node->data<<' ';
	}
}

void Tree::levelOrderVisit(Tree *node)
{
	if ( ! node)
	{
		return;
	}
	queue<Tree *> q;
	q.push(node);
	while ( ! q.empty())
	{
		Tree *tmp = q.front();
		cout<<tmp->data<<' ';
		q.pop();
		if (tmp->left)
		{
			q.push(tmp->left);
		}
		if (tmp->right)
		{
			q.push(tmp->right);
		}
	}
}

void Tree::notRecursionPreOrderVisit(Tree *node)
{
	stack<Tree *> s;
	Tree *t = node;
	while (!s.empty() || t)
	{
		if (t)
		{
			cout<<t->data<<' ';
			s.push(t);
			t = t->left;
		}
		else
		{
			t = s.top();
			s.pop();
			t = t->right;
		}
	}
}

void Tree::notRecursionInorderVisit(Tree *node)
{
	stack<Tree *> s;
	Tree *t = node;
	while (!s.empty() || t)
	{
		if (t)
		{
			s.push(t);
			t = t->left;
		}
		else
		{
			t = s.top();
			s.pop();
			cout<<t->data<<' ';
			t = t->right;
		}
	}
}

void Tree::notRecursionLastOrderVisit(Tree *node)
{
	stack<Tree *> s;
	Tree *t = node;
	Tree *pre = NULL;
	while(!s.empty() || t)
	{
		while (t)
		{
			s.push(t);
			t = t->left;
		}
		t = s.top();
		if (t->right==NULL || t->right==pre)
		{
			cout<<t->data<<' ';
			pre = t;
			t = NULL;
			s.pop();
		}
		else
		{
			t = t->right;
		}
	}
}

int main()
{
	Tree *t = NULL;
	t->create(t);
	t->preOrderVisit(t);
	cout<<endl;
	t->inOrderVisit(t);
	cout<<endl;
	t->lastOrderVisit(t);
	cout<<endl;
	t->levelOrderVisit(t);
	cout<<endl;
	t->notRecursionPreOrderVisit(t);
	cout<<endl;
	t->notRecursionInorderVisit(t);
	cout<<endl;
	t->notRecursionLastOrderVisit(t);
	cout<<endl;
	return 0;
}

输入输出

124005003600700
1 2 4 5 3 6 7
4 2 5 1 6 3 7
4 5 2 6 7 3 1
1 2 3 4 5 6 7
1 2 4 5 3 6 7
4 2 5 1 6 3 7
4 5 2 6 7 3 1

遍历 on ZRJ | 学习笔记

二叉树的遍历