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#include <cstdio>
#include <queue>
#include <cmath>
#include <cstring>
#include <string.h>
#include <algorithm>
#include <iostream>
using namespace std;

struct treenode {
	char data;
	treenode *left;
	treenode *right;
};

void aftervisit(treenode *root) {
	if (root == NULL) {
		return;
	}
	aftervisit(root->left);
	aftervisit(root->right);
	printf("%c", root->data);
}

treenode *rebuild(string pre, string mid) {
	if (pre.size() == 0) {
		return NULL;
	} else {
		char root_data = pre[0];
		int root_index = mid.find(root_data);
		//分割子树
		string pre_l = pre.substr(1, root_index);//左子树的pre序列
		string pre_r = pre.substr(root_index + 1);//右子树的pre序列
		string mid_l = mid.substr(0, root_index);//左子树的mid序列
		string mid_r = mid.substr(root_index + 1);//右子树的mid序列

		treenode *newnode = new treenode;
		newnode->data = root_data;
		newnode->left = reb...