Black&Red Tree

#include <algorithm>
#include <iostream>

using namespace std;

struct Node {
    long long key;
    Node * left;
    Node * right;

    Node(long long _key) {
        key = _key;
        left = nullptr;
        right = nullptr;
    }
};

void insert(Node * root, long long key) {
    if (key < root->key) {
        if (root->left == nullptr) {
            root->left = new Node(key);
        }
        insert(root->left, key);
        return;
    }
    if (key > root->key) {
        if (root->right == nullptr) {
            root->right = new Node(key);
        }
        insert(root->right, key);
        return;
    }
}

int height(Node * root) {
    if (root == nullptr) {
        return 0;
    }
    return max(height(root->left), height(root->right)) + 1;
}

int main() {
    long long num;
    cin >> num;
    Node * root = new Node(num);
    while (cin >> num) {
        if (num == 0) {
            break;
        }
        insert(root, num);
    }
    cout << height(root);
}