如果不写删除函数的话会超时，

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <string>
#include <vector>
#include <stack>
using namespace std;
//const int maxn=110;
 struct node{
	char data;
	struct node* lchild;
	struct node* rchild;
};//为什么我不定义变量直接用node不行
//node* pre[maxn],in[maxn];
int pos;
string s;
//node* tree;
//void create(node* &tree){
void create(node* &tree){
	if(pos>=s.size())return;
	if(s[pos]=='#'){
		tree=NULL;
		pos++;
	}else{
		tree=new node;
		tree->data=s[pos++];
		create(tree->lchild);
		create(tree->rchild);
	}
}
//void deletetree(node* &tree){
//	void deletetree(node* &tree){
//	if (tree != NULL){
//		if (tree->lchild != NULL){
//			deletetree(tree->lchild);
//			tree->lchild = NULL;
//		}
//
//		if (tree->rchild != NULL){
//			deletetree(tree->rchild);
//			tree->rchild = NULL;
//		}
//		delete tree;//关...