Notes

#include<iostream>
#include<cstdio>
#include<sstream>
#include<algorithm>
#define pow2(n) (1 << (n))
using namespace std;


struct avl_node
{
int data;
struct avl_node *left;
struct avl_node *right;
}*root;


class avlTree
{
public:
int height(avl_node *);
int diff(avl_node *);
avl_node *rr_rotation(avl_node *);
avl_node *ll_rotation(avl_node *);
avl_node *lr_rotation(avl_node *);
avl_node *rl_rotation(avl_node *);
avl_node* balance(avl_node *);
avl_node* insert(avl_node *, int );
void display(avl_node *, int);
void inorder(avl_node *);
void preorder(avl_node *);
void postorder(avl_node *);
avlTree()
{
root = NULL;
}
};


int main()
{
avlTree avl;


root = avl.insert(root, 20);
root = avl.insert(root, 15);
root = avl.insert(root, 40);
root = avl.insert(root, 60);
root = avl.insert(root, 30);
root = avl.insert(root, 35);
root = avl.insert(root, 65);
root = avl.insert(root, 75);
root = avl.insert(root, 10);
root = avl.insert(root, 5);
root = avl.insert(root, 8);
root = avl.insert(root, 12);
root = avl.insert(root, 11);
root = avl.insert(root, 13);


cout<<endl;

cout<<"Inorder Traversal:"<<endl;
avl.inorder(root);
cout<<endl;


return 0;
}


int avlTree::height(avl_node *temp)
{
int h = 0;
if (temp != NULL)
{
int l_height = height (temp->left);
int r_height = height (temp->right);
int max_height = max (l_height, r_height);
h = max_height + 1;
}
return h;
}


int avlTree::diff(avl_node *temp)
{
int l_height = height (temp->left);
int r_height = height (temp->right);
int b_factor= l_height - r_height;
return b_factor;
}


avl_node *avlTree::rr_rotation(avl_node *parent)
{
avl_node *temp;
temp = parent->right;
parent->right = temp->left;
temp->left = parent;
return temp;
}

avl_node *avlTree::ll_rotation(avl_node *parent)
{
avl_node *temp;
temp = parent->left;
parent->left = temp->right;
temp->right = parent;
return temp;
}


avl_node *avlTree::lr_rotation(avl_node *parent)
{
avl_node *temp;
temp = parent->left;
parent->left = rr_rotation (temp);
return ll_rotation (parent);
}


avl_node *avlTree::rl_rotation(avl_node *parent)
{
avl_node *temp;
temp = parent->right;
parent->right = ll_rotation (temp);
return rr_rotation (parent);
}


avl_node *avlTree::balance(avl_node *temp)
{
int bal_factor = diff (temp);
if (bal_factor > 1)
{
if (diff (temp->left) > 0)
temp = ll_rotation (temp);
else
temp = lr_rotation (temp);
}
else if (bal_factor < -1)
{
if (diff (temp->right) > 0)
temp = rl_rotation (temp);
else
temp = rr_rotation (temp);
}
return temp;
}

avl_node *avlTree::insert(avl_node *root, int value)
{
if (root == NULL)
{
root = new avl_node;
root->data = value;
root->left = NULL;
root->right = NULL;
return root;
}
else if (value < root->data)
{
root->left = insert(root->left, value);
root = balance (root);
}
else if (value >= root->data)
{
root->right = insert(root->right, value);
root = balance (root);
}
return root;
}



void avlTree::inorder(avl_node *tree)
{
if (tree == NULL)
return;
inorder (tree->left);
cout<<tree->data<<" ";
inorder (tree->right);
}