已知中序和后序，求先序

#include <stdio.h>
#include <stdlib.h>
#include<malloc.h>
typedef struct BiNode
{
int data;
struct BiNode *lchild;
struct BiNode *rchild;
}BiNode, *BiTree;
BiTree BuildPreTree(int *End, int *Mid, int n)
{
if(n <= 0) return NULL;
int *p = Mid;
while(*p != (End+n-1)) p++;
BiTree T;
T = (BiNode)malloc(sizeof(BiNode));
T->data = *p;
int len_l = p - Mid;
T->lchild = BuildPreTree(End, Mid, len_l);
T->rchild = BuildPreTree(End+len_l, Mid+len_l+1, n-len_l-1);
return T;
}
void CoutPre(BiTree T)
{
if( T != NULL ){
printf(" %d", T->data);
CoutPre(T->lchild);
CoutPre(T->rchild);
}

}
int main(){
int n,i;
int End[31],Mid[31];
scanf("%d",&n);
for(i = 0;i < n;i++)
scanf("%d",&End[i]);
for(i = 0;i < n;i++)
scanf("%d",&Mid[i]);
BiTree T = BuildPreTree(End, Mid, n);
printf(“Preorder:”);
CoutPre(T);
return 0;
}