#pragma once
#include <iostream>
using namespace std;


class avlTree
{
private:
	class node
	{
	public:
		double data;
		node* left;
		node* right;

		int height;

		node(double x)
		{
			data = x;
			left = nullptr;
			right = nullptr;
			height = 0;
		}
	};

	//uh oh, p's height value is sus.. 
	//set it to the correct number.
	void updateHeight(node* p)
	{
		p->height = 1 + max(height(p->left), height(p->right));
	}

	void leftRotation(node*& p)
	{
		node* A = p;
		node* B = p->right;
		node* bl = B->left;

		A->right = bl;
		B->left = A;
		p = B;

		updateHeight(A);
		updateHeight(B);
	}

	void rightRotation(node*& p)
	{
		node* A = p;
		node* B = p->left;
		node* br = B->right;

		A->left = br;
		B->right = A;
		p = B;

		updateHeight(A);
		updateHeight(B);
	}

	void rightLeftRotation(node * &p)
	{
		rightRotation(p->right);
		leftRotation(p);
	}

	void leftRightRotation(node*& p)
	{
		leftRotation(p->left);
		rightRotation(p);
	}

	//uh oh, p's balance is sus...
	//check if p is AVL balanced
	//If not, perform the proper rotation.
	void checkFixBalance(node*& p)
	{
		if (height(p->left) - height(p->right) >= 2)
		{//left height is too high
			if (height(p->left->left) > height(p->left->right))
				rightRotation(p);
			else
				leftRightRotation(p);
		}
		else if (height(p->right)-height(p->left) >= 2)
		{//right height is too high
			if (height(p->right->right) > height(p->right->left))
				leftRotation(p);
			else
				rightLeftRotation(p);
		}
		else
		{
			//The node is balanced!!! don't do anything.
		}
	}

	//Insert x into the tree rooted at node p.
	void insert(node*& p, double x)
	{
		if (p == nullptr)//tree is empty)
			p = new node(x);
		else
		{
			if (x < p->data)
			{
				//insert to the left
				insert(p->left, x);//the left tree)
			}
			else
			{
				//insert to the right
				insert(p->right, x);
			}

			updateHeight(p);
			checkFixBalance(p);
		}
	}

	node* root;

	//print all items in tree rooted at node p.
	//In-order traversal
	void display(node* p)
	{
		if (p == nullptr)
		{
			//don't do anything, no nodes
		}
		else
		{
			display(p->left);
			cout << p->data << endl;
			display(p->right);
		}
	}

	//return the height of tree rooted at node p.
	int height(node* p)
	{
		if (p == nullptr)
			return -1;
		else
			return p->height;
	}

public:

	avlTree()
	{
		root = nullptr;
	}

	void insert(double x)
	{
		insert(root, x);
	}

	void display()
	{
		display(root);
	}

	int height()
	{
		return height(root);
	}
};