分层遍历二叉树（编程之美3.10）

// 3_10.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include <vector>

struct Node
{
	int data;
	Node * left;
	Node * right;
};

int printByLevel(Node * root, int level)
{
	if(!root || level < 0)
		return 0;
	if(level == 0)
	{
		printf("%d ",root->data);
		return 1;
	}
	return printByLevel(root->left, level-1) + printByLevel(root->right, level-1);

}

//不使用queue的原因是不能区分每一层的结束，没法分行输出
void print(Node * root)
{
	std::vector<Node*> vec;
	vec.push_back(root);
	int cur = 0;
	int last = 1;
	while(cur<vec.size())
	{
		last = vec.size();
		while(cur < last)
		{
			printf("%d ", vec[cur]->data);
			if(vec[cur]->left != NULL)
				vec.push_back(vec[cur]->left);
			if(vec[cur]->right != NULL)
				vec.push_back(vec[cur]->right);
			cur++;
		}
		printf("\n");
	}
}


int _tmain(int argc, _TCHAR* argv[])
{
	Node * root = new Node();
	Node * n1 = new Node();
	Node * n2 = new Node();
	Node * n3 = new Node();
	
	root->data = 0;
	root->left = n1;
	root->right = n2;
	n1->left = NULL;
	n1->right = NULL;
	n2->left = n3;
	n2->right = NULL;
	n3->left = NULL;
	n3->right = NULL;
	n1->data = 1;
	n2->data = 2;
	n3->data = 3;

	printByLevel(root,1);
	printf("\n");
	print(root);
	
	return 0;
}