hdu1710 二叉树的遍历

Problem Description

已知前序和中序 求后序

Input

The input contains several test cases. The first line of each test case contains a single integer n (1<=n<=1000), the number of vertices of the binary tree. Followed by two lines, respectively indicating the preorder sequence and inorder sequence. You can assume they are always correspond to a exclusive binary tree.

Output

For each test case print a single line specifying the corresponding postorder sequence.

Sample Input

9

1 2 4 7 3 5 8 9 6

4 7 2 1 8 5 9 3 6

Sample Output

7 4 2 8 9 5 6 3 1

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<cmath>
using namespace std;
int a[],b[];
void hxbl(int x,int y,int n,int flag)
{
    if(n==)
    {
        printf("%d ",b[y]);
        return;
    }
    if(n<=) return;
    int i;
    for(i=; a[x]!=b[y+i]; i++);
    hxbl(x+,y,i,);
    hxbl(x+i+,y+i+,n-i-,);
    if(flag==) printf("%d",a[x]);
    else printf("%d ",a[x]);
}
int main()
{
    int n;
    while(scanf("%d",&n)==)
    {
        for(int i=; i<=n; i++) scanf("%d",a+i);
        for(int i=; i<=n; i++) scanf("%d",b+i);
        hxbl(,,n,);
        printf("\n");
    }
    return ;
}