#include<bits/stdc++.h>
using namespace std;

int ans;
unordered_map<int,int> hmap;

void postTraverse(vector<int>& post,vector<int>& in, int post_st,int post_ed,int in_st,int in_ed){
    // if(post_ed > post_ed || in_st > in_ed)return;
    if(post_st == post_ed || in_st == in_ed){
        cout<<post[post_ed]<<endl;
        return;
    }

    int root = post[post_ed];

    // int k;
    // for(int i = in_st;i<=in_ed;i++){
    //     if(in[i] == root){
    //         k = i;
    //         break;
    //     }
    // }
    int k = hmap[root];

    int right_num = in_ed - k,left_num = k - in_st;

    if(right_num > 0){
        //往右走
        postTraverse(post,in,post_ed - right_num, post_ed-1,k+1,in_ed);
    }else{
        //往左走
        postTraverse(post,in,post_st,post_ed - right_num - 1,in_st,k-1);
    }


}


int main(){
    int n;
    cin>>n;
    vector<int> post(n,0);
    vector<int> in(n,0);

    for(int i = 0;i<n;i++) cin>>post[i];
    for(int i = 0;i<n;i++){
         cin>>in[i];
         hmap[in[i]] = i;

    }

    postTraverse(post,in,0,n-1,0,n-1);
    // cout<<ans;


}

算法1

(暴力枚举) $O(n^2)$

blablabla

时间复杂度

参考文献

C++ 代码

blablabla

算法2

(暴力枚举) $O(n^2)$

blablabla

时间复杂度

参考文献

C++ 代码

blablabla