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#ifndef AVL_TREE_IMPL
#define AVL_TREE_IMPL
#include<algorithm>
#include<cassert>
#include<cstddef>
template<class T>
class AVLTree {
private:
struct Node {
T data;
Node* left;
Node* right;
int height;
static int getHeight(const Node* r) {
if (r == nullptr)
return 0;
return r->height;
}
static void rotateLeft(Node*& r) {
assert(r->right != nullptr);
Node* originalRight = r->right;
r->right = originalRight->left;
originalRight->left = r;
r = originalRight;
}
static void rotateRight(Node*& r) {
assert(r->left != nullptr);
Node* originalLeft = r->left;
r->left = originalLeft->right;
originalLeft->right = r;
r = originalLeft;
}
static void balanceLeft(Node*& r) {
assert(r);
int rootBalance = getBalanceFactor(r);
int leftBalance = getBalanceFactor(r->left);
if (rootBalance == -2) {
if (leftBalance == 1) {
rotateRight(r->left);
updateHeight(r->left->left);
updateHeight(r->left);
}
rotateLeft(r);
updateHeight(r->left);
updateHeight(r);
}
}
static void balanceRight(Node*& r) {
assert(r);
int rootBalance = getBalanceFactor(r);
int rightBalance = getBalanceFactor(r->right);
if (rootBalance == 2) {
if (rightBalance == -1) {
rotateRight(r->right);
updateHeight(r->right->right);
updateHeight(r->right);
}
rotateLeft(r);
updateHeight(r->left);
updateHeight(r);
}
}
static void updateHeight(Node* r) {
if (r == nullptr)
return;
r->height = std::max(getHeight(r->left), getHeight(r->right)) + 1;
}
static int getBalanceFactor(const Node* r) {
if (r == nullptr)
return 0;
return getHeight(r->right) - getHeight(r->left);
}
Node(const T& d, Node* l, Node* r, int h) : data{ d }, left{ l }, right{ r }, height{ h } {}
};
Node* findMinNode(Node* r) {
if (r->left == nullptr)
return r;
return findMinNode(r->left);
}
void insertRec(Node*& r, const T& elem) {
if (r == nullptr) {
r = new Node(elem, nullptr, nullptr, 1);
size++;
return;
}
if (r->data < elem) {
insertRec(r->right, elem);
Node::updateHeight(r->right);
Node::balanceRight(r);
}
else if (r->data > elem) {
insertRec(r->left, elem);
Node::updateHeight(r->left);
Node::balanceLeft(r);
}
}
bool removeRec(Node*& r, const T& elem) {
if (r == nullptr) {
return false;
}
if (r->data < elem) {
removeRec(r->right, elem);
Node::updateHeight(r);
Node::balanceLeft(r);
}
else if (r->data > elem) {
removeRec(r->left, elem);
Node::updateHeight(r);
Node::balanceRight(r);
}
else {
if (!r->left && !r->right) {
delete r;
r = nullptr;
return true;
}
else if (r->left && !r->right) {
Node* toDelete = r;
r = r->left;
delete toDelete;
}
else if (!r->left && r->right) {
Node* toDelete = r;
r = r->right;
delete toDelete;
}
else {
root->data = findMinNode(root->right)->data;
removeRec(r->right, r->data);
Node::updateHeight(r);
Node::balanceRight(r);
}
}
return true;
}
void freeRec(Node* r) {
if (r == nullptr)
return;
freeRec(r->left);
freeRec(r->right);
delete r;
}
public:
AVLTree() : root{ nullptr }, size{ 0 } {}
// TBI
AVLTree(const AVLTree<T>& other) = delete;
AVLTree& operator=(const AVLTree<T>& other) = delete;
bool contains(const T& elem);
void insert(const T& elem) {
insertRec(root, elem);
}
bool remove(const T& elem) {
return removeRec(root, elem);
}
~AVLTree() {
freeRec(root);
}
private:
Node* root;
size_t size;
};
#endif
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