【100题】二叉树的层序遍历(广度优先遍历)

#include <iostream>
#include <deque>
using namespace std;

//树结构
struct BTreeNode
{
	int m_nValue;
	BTreeNode *m_pLeft;
	BTreeNode *m_Right;
};

//层序遍历二叉树，即广度优先。
void Print(BTreeNode *pNode)
{
	if(!pNode)
	{
		return ;
	}

	deque<BTreeNode *> dequeTree;
	dequeTree.push_back(pNode);

	while(dequeTree.size())
	{
		BTreeNode *p = dequeTree.front();
		dequeTree.pop_front();

		cout << p->m_nValue <<' ';

		if(p->m_pLeft)
		{
			dequeTree.push_back(p->m_pLeft);
		}
		if(p->m_Right)
		{
			dequeTree.push_back(p->m_Right);
		}
	}
}

//按照先序创建二叉树,0表示空  
BTreeNode *CreateTree()  
{  
    int ch;  
    cin>> ch;  
    if(ch == 0)  
    {  
         return NULL;  
    }  
    else  
    {  
         BTreeNode *root = new BTreeNode();  
         root->m_nValue = ch;  
         root->m_pLeft = CreateTree();  
         root->m_Right = CreateTree();  
         return root;  
    }  
}  
  
void main()
{
	BTreeNode *root = NULL;
	cout <<"创建树：";
	root = CreateTree();
	cout << "层序遍历：";
	Print(root);
	cout << endl;
}

创建树：1 2 4 0 0 5 0 0 3 6 0 0 7 0 0
层序遍历：1 2 3 4 5 6 7
请按任意键继续. . .