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#pragma once
#include <iostream>
#include <functional>
#include <stack>
#include <vector>
template <class T, typename Compare = std::less<T>>
class Bst
{
private:
struct Node
{
T data;
Node* left;
Node* right;
Node(const T& data, Node* left = nullptr, Node* right = nullptr) : data(data), left(left), right(right) {}
};
Node* root = nullptr;
size_t size = 0;
Compare comp; // comparator instance
Node** findMinNode(Node** root);
void free(Node* current);
Node* copy(Node* current);
public:
Bst() = default;
explicit Bst(const Compare& comparator) : comp(comparator) {}
Bst(const Bst<T, Compare>& other);
Bst<T, Compare>& operator=(const Bst<T, Compare>& other);
~Bst();
bool insert(const T& data);
bool contains(const T& data) const;
bool remove(const T& data);
size_t getSize() const;
bool isEmpty() const;
class ForwardIterator
{
private:
std::stack<Node*> nodeStack;
void pushLeft(Node* node)
{
while (node != nullptr)
{
nodeStack.push(node);
node = node->left;
}
}
public:
ForwardIterator(Node* root = nullptr)
{
pushLeft(root);
}
T& operator*() const
{
return nodeStack.top()->data;
}
ForwardIterator& operator++()
{
Node* right = nodeStack.top()->right;
nodeStack.pop();
pushLeft(right);
return *this;
}
ForwardIterator operator++(int)
{
ForwardIterator copy(*this);
++(*this);
return copy;
}
bool operator!=(const ForwardIterator& other) const
{
return !(*this == other);
}
bool operator==(const ForwardIterator& other) const
{
return (other.nodeStack.empty() && nodeStack.empty()) || (nodeStack.size() && other.nodeStack.size() && nodeStack.top() == other.nodeStack.top());
}
};
ForwardIterator begin() const
{
return ForwardIterator(root);
}
ForwardIterator end() const
{
return ForwardIterator(nullptr);
}
};
template <class T, typename Compare>
bool Bst<T, Compare>::insert(const T& data)
{
Node** current = &root;
while (*current)
{
if (comp(data, (*current)->data))
current = &(*current)->left;
else if (comp((*current)->data, data))
current = &(*current)->right;
else
return false; // Data already exists
}
*current = new Node(data);
size++;
return true;
}
template <class T, typename Compare>
bool Bst<T, Compare>::contains(const T& data) const
{
Node* current = root;
while (current)
{
if (comp(data, current->data))
current = current->left;
else if (comp(current->data, data))
current = current->right;
else
return true;
}
return false;
}
template <class T, typename Compare>
typename Bst<T, Compare>::Node** Bst<T, Compare>::findMinNode(Node** root)
{
Node** current = root;
while ((*current)->left)
{
current = &(*current)->left;
}
return current;
}
template <class T, typename Compare>
bool Bst<T, Compare>::remove(const T& data)
{
Node** current = &root;
while (*current)
{
if (comp(data, (*current)->data))
current = &(*current)->left;
else if (comp((*current)->data, data))
current = &(*current)->right;
else
break;
}
if (!(*current))
return false; // Data not found
Node* toDelete = *current;
if (!(*current)->left && !(*current)->right)
*current = nullptr; // Node has no children
else if (!(*current)->right)
*current = (*current)->left; // Node has only left child
else if (!(*current)->left)
*current = (*current)->right; // Node has only right child
else
{
Node** rightMin = findMinNode(&(*current)->right);
*current = *rightMin;
*rightMin = (*rightMin)->right;
(*current)->left = toDelete->left;
(*current)->right = toDelete->right;
}
delete toDelete;
size--;
return true;
}
template <class T, typename Compare>
size_t Bst<T, Compare>::getSize() const
{
return size;
}
template <class T, typename Compare>
bool Bst<T, Compare>::isEmpty() const
{
return getSize() == 0;
}
template <class T, typename Compare>
typename Bst<T, Compare>::Node* Bst<T, Compare>::copy(Node* current)
{
if (!current)
return nullptr;
Node* res = new Node(current->data);
res->left = copy(current->left);
res->right = copy(current->right);
return res;
}
template <class T, typename Compare>
void Bst<T, Compare>::free(Node* current)
{
if (!current)
return;
free(current->left);
free(current->right);
delete current;
}
template <class T, typename Compare>
Bst<T, Compare>::Bst(const Bst<T, Compare>& other) : comp(other.comp)
{
root = copy(other.root);
size = other.size;
}
template <class T, typename Compare>
Bst<T, Compare>& Bst<T, Compare>::operator=(const Bst<T, Compare>& other)
{
if (this != &other)
{
free(root);
root = copy(other.root);
size = other.size;
comp = other.comp;
}
return *this;
}
template <class T, typename Compare>
Bst<T, Compare>::~Bst()
{
free(root);
}
void treeSort(std::vector<int>& v)
{
Bst<int> bst;
for (int i = 0; i < v.size(); i++)
bst.insert(v.at(i));
unsigned index = 0;
for (auto it = bst.begin(); it != bst.end(); it++)
v.at(index++) = *it;
}
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