题目地址：

已知二叉树先序和中序求后序。

#include 
     
      #include 
      
       int a[1001], cnt;typedef struct node{    int date ;    node *lchild , *rchild ;}*tree;int getk(int ch,int ino[],int is,int n){    for(int i = is ; i <= is + n -1 ; i++)        if(ino[i]==ch)return i;}void gettree(tree &t,int pre[],int ino[],int ps,int is,int n){    if(n==0) t = NULL;    else    {        t = new node;        t->date = pre[ps];        int k = getk(pre[ps],ino,is,n);        if(k == is) t->lchild = NULL;        else            gettree(t->lchild,pre,ino,ps+1,is,k-is);        if(k == is+n-1) t->rchild = NULL;        else            gettree(t->rchild,pre,ino,ps+1+(k-is),k+1,n-1-(k-is));    }}void pritree1(tree t){    if(t)    {        pritree1(t->lchild);        pritree1(t->rchild);        a[cnt++]=t->date;    }}int main(){    int i, n, t;    int pre[1001] , ino[1001] ;    while(scanf("%d", &n)!=EOF)    {        cnt=0;        tree head;        for(i=0; i