一道给出前序和中序遍历的结果，重构二叉树并返回后序遍历的结果。
需要主要的地方是好好理解题目意思

#include<cstdio>
#include<cstring>
#include<vector>
#include<stack>
#include<iostream>
using namespace std;
vector<int> pre,in,post;
struct node{
	int value;
	node *left,*right;
	node(int x):value(x),left(NULL),right(NULL){}
};

void create(node* &root, int preL,int  preR, int inL, int inR){
	if(preL > preR) return;
	root = new node(pre[preL]);
	int k=inL;
	while(in[k] != pre[preL]){
		k++;
	}
	int left = k -inL;
	create(root->left, preL+1, preL+left,inL, k -1);
	create(root->right, preL+left+1, preR,k+1, inR);
}
void postorder(node* root){
	if(root == NULL) return;
	postorder(root->left);
	postorder(root->right);
	post.push_back(root->value);
}


int main(){
	int n,v;
	char op[10];
	stack<int> st;
	node* root=NULL;
	scanf("%d",&n);
	for(int i=0;i<2*n;i++){
		scanf("%s",op);
		if(strcmp(op,"Push")==0){
			scanf("%d",&v);
			st.push(v);
			pre.push_back(v);
		}else{
			in.push_back(st.top());
			st.pop();
		} 
	}
	
	
	create(root,0,pre.size()-1, 0, in.size()-1);
	postorder(root);
	for(int i=0;i<post.size();i++){
		if(i>0) printf(" ");
		printf("%d",post[i]);
	}
	return 0;
}