dfs/bst/valid_binary_search_tree

class Node:
    def __init__(self, val, left=None, right=None):
        self.val = val
        self.left = left
        self.right = right

import sys
def valid_bst(root: Node) -> bool:
    """
    Traverse the tree with DFS, and check if the left val and right val are between for curr val, return max val
    """

# this function builds a tree from input; you don't have to modify it
# learn more about how trees are encoded in https://algo.monster/problems/serializing_tree
def build_tree(nodes, f):
    val = next(nodes)
    if val == "x":
        return None
    left = build_tree(nodes, f)
    right = build_tree(nodes, f)
    return Node(f(val), left, right)

if __name__ == "__main__":
    root = build_tree(iter(input().split()), int)
    res = valid_bst(root)
    print("true" if res else "false")

#include <algorithm>
#include <iostream>
#include <iterator>
#include <sstream>
#include <string>
#include <vector>

template<typename T>
struct Node {
    T val;
    Node<T>* left;
    Node<T>* right;

    explicit Node(T val, Node<T>* left = nullptr, Node<T>* right = nullptr)
        : val{val}, left{left}, right{right} {}

    ~Node() {
        delete left;
        delete right;
    }
};

bool valid_bst(Node<int>* root) {
    // WRITE YOUR BRILLIANT CODE HERE
    return false;
}

// this function builds a tree from input
// learn more about how trees are encoded in https://algo.monster/problems/serializing_tree
template<typename T, typename Iter, typename F>
Node<T>* build_tree(Iter& it, F f) {
    std::string val = *it;
    ++it;
    if (val == "x") return nullptr;
    Node<T>* left = build_tree<T>(it, f);
    Node<T>* right = build_tree<T>(it, f);
    return new Node<T>{f(val), left, right};
}

template<typename T>
std::vector<T> get_words() {
    std::string line;
    std::getline(std::cin, line);
    std::istringstream ss{line};
    ss >> std::boolalpha;
    std::vector<T> v;
    std::copy(std::istream_iterator<T>{ss}, std::istream_iterator<T>{}, std::back_inserter(v));
    return v;
}

int main() {
    std::vector<std::string> root_vec = get_words<std::string>();
    auto root_it = root_vec.begin();
    Node<int>* root = build_tree<int>(root_it, [](auto s) { return std::stoi(s); });
    bool res = valid_bst(root);
    std::cout << std::boolalpha << res << '\n';
}

No solution file found.