1136. Parliament - Timus

#include <bits/stdc++.h>

using namespace std;

struct Tree {
    int info;
    Tree *parent, *left, *right;
};

Tree *tree;

void Insert(Tree **l, int x, Tree *parent) {
    Tree *p;
    if(*l == NULL) {
        p = new Tree;
        p -> info = x;
        p -> left = p -> right = nullptr;
        p -> parent = parent;
        *l = p;
        return;
    }
    if(x < (*l) -> info)
        Insert(&((*l) -> left), x, *l);
    else
        Insert(&((*l) -> right), x, *l);
}

void PostOrder_traversal(Tree *l) {
    if (l != nullptr) {
        PostOrder_traversal(l -> right);
        PostOrder_traversal(l -> left);
        cout << l -> info << '\n';
    }
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    int N;
    cin >> N;
    vector < int > a(N);
    for(int& x : a)
        cin >> x;
    for(int i = N - 1; i >= 0; --i)
        Insert(&tree, a[i], nullptr);
    PostOrder_traversal(tree);
}