关于树的先序遍历，层次遍历，后序遍历

// 已知后序遍历和中序遍历，求层次遍历





#include<iostream>
#include<cstdio>
#include<vector>
#include<algorithm>
#include<map>
using namespace std;
#define STDIN freopen("in.txt", "r", stdin);freopen("out.txt", "w", stdout);

const int N = 35;

int in[N], post[N];

vector<pair<int,int> > vec;

bool cmp(pair<int,int> a, pair<int, int> b)
{
    return a.second < b.second;
}

void level_order(int root, int start, int end, int index)
{
    if (start > end)
        return ;
    int i = start;
    while (i < end && in[i] != post[root]) i++;

    // cout << post[root] << " " << index << endl;
    
    vec.push_back({post[root], index});

    level_order(root - (end - i + 1), start, i-1, 2*index);
    level_order(root-1, i + 1, end, 2*index + 1);
    
}

int main()
{
//     STDIN
    int n;
    cin >> n;
    for (int i = 1; i <= n; i++) cin >>  post[i];

    for (int i = 1; i <= n; i++) cin >> in[i];

    level_order(n,1,n,1);

    sort(vec.begin(), vec.end(), cmp);
    int len = vec.size();
    for(int i = 0; i < len; i++)
    {
        printf("%d%c", vec[i], " 
"[i == len-1]);
    }

}