The document is a C++ implementation of a generic binary search tree (BST) template class. It includes definitions for various member functions such as insertion, searching, and deletion, alongside private node structures and utility functions for tree visualization and printing. However, many methods contain 'todo' comments indicating they have not yet been implemented.

1. Need help with the TODO's (DONE IN C++)
#pragma once
#include <functional> // std::less
#include <iostream>
#include <queue> // std::queue
#include <utility> // std::pair
template <typename K, typename V, typename Comparator = std::less<K>>
class BinarySearchTree
{
public:
using key_type = K;
using value_type = V;
using key_compare = Comparator;
using pair = std::pair<key_type, value_type>;
using pointer = pair*;
using const_pointer = const pair*;
using reference = pair&;
using const_reference = const pair&;
using difference_type = ptrdiff_t;
using size_type = size_t;

2. private:
struct BinaryNode
{
pair element;
BinaryNode *left;
BinaryNode *right;
BinaryNode( const_reference theElement, BinaryNode *lt, BinaryNode *rt )
: element{ theElement }, left{ lt }, right{ rt } { }
BinaryNode( pair && theElement, BinaryNode *lt, BinaryNode *rt )
: element{ std::move( theElement ) }, left{ lt }, right{ rt } { }
};
using node = BinaryNode;
using node_ptr = node*;
using const_node_ptr = const node*;
node_ptr _root;
size_type _size;
key_compare comp;
public:
BinarySearchTree() {

3. // TODO
}
BinarySearchTree( const BinarySearchTree & rhs ) {
// TODO
}
BinarySearchTree( BinarySearchTree && rhs ) {
// TODO
}
~BinarySearchTree() {
// TODO
}
const_reference min() const { return min( _root )->element; }
const_reference max() const { return max( _root )->element; }
const_reference root() const {
// TODO
}
bool contains( const key_type & x ) const { return contains( x, _root ); }
value_type & find( const key_type & key ) { return find( key, _root )->element.second; }
const value_type & find( const key_type & key ) const { return find( key, _root )-
>element.second; }
bool empty() const {
// TODO
}

4. size_type size() const {
// TODO
}
void clear() {
clear( _root );
_size = 0;
}
void insert( const_reference x ) { insert( x, _root ); }
void insert( pair && x ) { insert( std::move( x ), _root ); }
void erase( const key_type & x ) { erase(x, _root); }
BinarySearchTree & operator=( const BinarySearchTree & rhs ) {
// TODO
}
BinarySearchTree & operator=( BinarySearchTree && rhs ) {
// TODO
}
private:
void insert( const_reference x, node_ptr & t ) {
// TODO
}

5. void insert( pair && x, node_ptr & t ) {
// TODO
}
void erase( const key_type & x, node_ptr & t ) {
// TODO
}
const_node_ptr min( const_node_ptr t ) const {
// TODO
}
const_node_ptr max( const_node_ptr t ) const {
// TODO
}
bool contains( const key_type & x, const_node_ptr t ) const {
// TODO
}
node_ptr find( const key_type & key, node_ptr t ) {
// TODO
}
const_node_ptr find( const key_type & key, const_node_ptr t ) const {
// TODO

6. }
void clear( node_ptr & t ) {
// TODO
}
node_ptr clone ( const_node_ptr t ) const {
// TODO
}
public:
template <typename KK, typename VV, typename CC>
friend void printLevelByLevel( const BinarySearchTree<KK, VV, CC>& bst, std::ostream & out
);
template <typename KK, typename VV, typename CC>
friend std::ostream& printNode(std::ostream& o, const typename BinarySearchTree<KK, VV,
CC>::node& bn);
template <typename KK, typename VV, typename CC>
friend void printTree( const BinarySearchTree<KK, VV, CC>& bst, std::ostream & out );
template <typename KK, typename VV, typename CC>
friend void printTree(typename BinarySearchTree<KK, VV, CC>::const_node_ptr t,
std::ostream & out, unsigned depth );

7. template <typename KK, typename VV, typename CC>
friend void vizTree(
typename BinarySearchTree<KK, VV, CC>::const_node_ptr node,
std::ostream & out,
typename BinarySearchTree<KK, VV, CC>::const_node_ptr prev
);
template <typename KK, typename VV, typename CC>
friend void vizTree(
const BinarySearchTree<KK, VV, CC> & bst,
std::ostream & out
);
};
template <typename KK, typename VV, typename CC>
std::ostream& printNode(std::ostream & o, const typename BinarySearchTree<KK, VV,
CC>::node & bn) {
return o << '(' << bn.element.first << ", " << bn.element.second << ')';
}
template <typename KK, typename VV, typename CC>
void printLevelByLevel( const BinarySearchTree<KK, VV, CC>& bst, std::ostream & out =
std::cout ) {
using node = typename BinarySearchTree<KK, VV, CC>::node;

8. using node_ptr = typename BinarySearchTree<KK, VV, CC>::node_ptr;
using const_node_ptr = typename BinarySearchTree<KK, VV, CC>::const_node_ptr;
// TODO -- Guide in Instructions
}
template <typename KK, typename VV, typename CC>
void printTree( const BinarySearchTree<KK, VV, CC> & bst, std::ostream & out = std::cout ) {
printTree<KK, VV, CC>(bst._root, out ); }
template <typename KK, typename VV, typename CC>
void printTree(typename BinarySearchTree<KK, VV, CC>::const_node_ptr t, std::ostream &
out, unsigned depth = 0 ) {
if (t != nullptr) {
printTree<KK, VV, CC>(t->right, out, depth + 1);
for (unsigned i = 0; i < depth; ++i)
out << 't';
printNode<KK, VV, CC>(out, *t) << 'n';
printTree<KK, VV, CC>(t->left, out, depth + 1);
}
}
template <typename KK, typename VV, typename CC>
void vizTree(
typename BinarySearchTree<KK, VV, CC>::const_node_ptr node,

9. std::ostream & out,
typename BinarySearchTree<KK, VV, CC>::const_node_ptr prev = nullptr
) {
if(node) {
std::hash<KK> khash{};
out << "t" "node_" << (uint32_t) khash(node->element.first)
<< "[label="" << node->element.first
<< " [" << node->element.second << "]"];" << std::endl;
if(prev)
out << "tnode_" << (uint32_t) khash(prev->element.first) << " -> ";
else
out << "t";
out << "node_" << (uint32_t) khash(node->element.first) << ";" << std::endl;
vizTree<KK, VV, CC>(node->left, out, node);
vizTree<KK, VV, CC>(node->right, out, node);
}
}
template <typename KK, typename VV, typename CC>
void vizTree(
const BinarySearchTree<KK, VV, CC> & bst,
std::ostream & out = std::cout

10. ) {
out << "digraph Tree {" << std::endl;
vizTree<KK, VV, CC>(bst._root, out);
out << "}" << std::endl;
}