4-15 根据后序和中序遍历输出先序遍历 (15 分)

7
2 3 1 5 7 6 4
1 2 3 4 5 6 7

Preorder: 4 1 3 2 6 5 7

#include<iostream>
using namespace std;
int hou[33];
int zhong[33];
int flag=0,n;
struct tree{
	int data;
	tree *left,*right;
};
tree* creat(int root,int begin,int end){//end =length+begin 
	if(end<begin)return NULL;
	tree *t=(tree*)malloc(sizeof(tree));
	t->data=hou[root];
    int i;
	for(i=begin;hou[root]!=zhong[i];i++);
	t->left=creat(root-1-(end-i),begin,i-1);
	t->right=creat(root-1,i+1,end);
	return t;
}
void mlr(tree * t){
	if(t==NULL) return ;
	if(flag)cout<<" ";
    flag=1;
	cout<<t->data;
	mlr(t->left);
	mlr(t->right);
}
int main(){
	cin>>n;
	for(int i=0;i<n;i++)cin>>hou[i];
	for(int i=0;i<n;i++)cin>>zhong[i];
	cout<<"Preorder: ";
	mlr(creat(n-1,0,n-1));
	return 0;
}