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[1005],b[1005];
void hxbl(int x,int y,int n,int flag)
{
    if(n==1)
    {
        printf("%d ",b[y]);
        return;
    }
    if(n<=0) return;
    int i;
    for(i=0; a[x]!=b[y+i]; i++);
    hxbl(x+1,y,i,0);
    hxbl(x+i+1,y+i+1,n-i-1,0);
    if(flag==1) printf("%d",a[x]);
    else printf("%d ",a[x]);
}
int main()
{
    int n;
    while(scanf("%d",&n)==1)
    {
        for(int i=1; i<=n; i++) scanf("%d",a+i);
        for(int i=1; i<=n; i++) scanf("%d",b+i);
        hxbl(1,1,n,1);
        printf("\n");
    }
    return 0;
}