#include <iostream>
using namespace std;
typedef struct tagNode
{
	char data;
	tagNode *lchild;
	tagNode *rchild;
}*PNode;
void createtree(PNode &T)
{
	char c;
	cin >> c;
	if(c == ',')return;
	else
	{
		T = new tagNode;
		T->data = http://www.mamicode.com/c;>
求一颗二叉树中最远的两个节点的距离