Avl Tree

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-2

class treeNode(object):
	def __init__(self, value):
		self.value = value
		self.l = None
		self.r = None
		self.h = 1

class AVLTree(object):

	def insert(self, root, key):
	
		if not root:
			return treeNode(key)
		elif key < root.value:
			root.l = self.insert(root.l, key)
		else:
			root.r = self.insert(root.r, key)

		root.h = 1 + max(self.getHeight(root.l),
						self.getHeight(root.r))

		b = self.getBal(root)

		if b > 1 and key < root.l.value:
			return self.rRotate(root)

		if b < -1 and key > root.r.value:
			return self.lRotate(root)

		if b > 1 and key > root.l.value:
			root.l = self.lRotate(root.l)
			return self.rRotate(root)

		if b < -1 and key < root.r.value:
			root.r = self.rRotate(root.r)
			return self.lRotate(root)

		return root

	def lRotate(self, z):

		y = z.r
		T2 = y.l

		y.l = z
		z.r = T2

		z.h = 1 + max(self.getHeight(z.l),
						self.getHeight(z.r))
		y.h = 1 + max(self.getHeight(y.l),
						self.getHeight(y.r))

		return y

	def rRotate(self, z):

		y = z.l
		T3 = y.r

		y.r = z
		z.l = T3

		z.h = 1 + max(self.getHeight(z.l),
						self.getHeight(z.r))
		y.h = 1 + max(self.getHeight(y.l),
						self.getHeight(y.r))

		return y

	def getHeight(self, root):
		if not root:
			return 0

		return root.h

	def getBal(self, root):
		if not root:
			return 0

		return self.getHeight(root.l) - self.getHeight(root.r)

	def preOrder(self, root):

		if not root:
			return

		print("{0} ".format(root.value), end="")
		self.preOrder(root.l)
		self.preOrder(root.r)

Tree = AVLTree()
root = None

root = Tree.insert(root, 1)
root = Tree.insert(root, 2)
root = Tree.insert(root, 3)
root = Tree.insert(root, 4)
root = Tree.insert(root, 5)
root = Tree.insert(root, 6)

# Preorder Traversal
print("Preorder traversal of the",
	"constructed AVL tree is")
Tree.preOrder(root)
print()

Popularity 10/10 Helpfulness 1/10 Language python

Source: favtutor.com

Tags: avl-tree python

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Contributed on Oct 04 2021

Itchy Impala

0 Answers Avg Quality 2/10

avl tree c++

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2

#include <stdio.h>
#include "avltree.h"
/*
    remove all nodes of an AVL tree
*/
void dispose(node* t)
{
    if( t != NULL )
    {
        dispose( t->left );
        dispose( t->right );
        free( t );
    }
}

/*
    find a specific node's key in the tree
*/
node* find(int e, node* t )
{
    if( t == NULL )
        return NULL;
    if( e < t->data )
        return find( e, t->left );
    else if( e > t->data )
        return find( e, t->right );
    else
        return t;
}

/*
    find minimum node's key
*/
node* find_min( node* t )
{
    if( t == NULL )
        return NULL;
    else if( t->left == NULL )
        return t;
    else
        return find_min( t->left );
}

/*
    find maximum node's key
*/
node* find_max( node* t )
{
    if( t != NULL )
        while( t->right != NULL )
            t = t->right;

    return t;
}

/*
    get the height of a node
*/
static int height( node* n )
{
    if( n == NULL )
        return -1;
    else
        return n->height;
}

/*
    get maximum value of two integers
*/
static int max( int l, int r)
{
    return l > r ? l: r;
}

/*
    perform a rotation between a k2 node and its left child

    note: call single_rotate_with_left only if k2 node has a left child
*/

static node* single_rotate_with_left( node* k2 )
{
    node* k1 = NULL;

    k1 = k2->left;
    k2->left = k1->right;
    k1->right = k2;

    k2->height = max( height( k2->left ), height( k2->right ) ) + 1;
    k1->height = max( height( k1->left ), k2->height ) + 1;
    return k1; /* new root */
}

/*
    perform a rotation between a node (k1) and its right child

    note: call single_rotate_with_right only if
    the k1 node has a right child
*/

static node* single_rotate_with_right( node* k1 )
{
    node* k2;

    k2 = k1->right;
    k1->right = k2->left;
    k2->left = k1;

    k1->height = max( height( k1->left ), height( k1->right ) ) + 1;
    k2->height = max( height( k2->right ), k1->height ) + 1;

    return k2;  /* New root */
}

/*

    perform the left-right double rotation,

    note: call double_rotate_with_left only if k3 node has
    a left child and k3's left child has a right child
*/

static node* double_rotate_with_left( node* k3 )
{
    /* Rotate between k1 and k2 */
    k3->left = single_rotate_with_right( k3->left );

    /* Rotate between K3 and k2 */
    return single_rotate_with_left( k3 );
}

/*
    perform the right-left double rotation

   notes: call double_rotate_with_right only if k1 has a
   right child and k1's right child has a left child
*/



static node* double_rotate_with_right( node* k1 )
{
    /* rotate between K3 and k2 */
    k1->right = single_rotate_with_left( k1->right );

    /* rotate between k1 and k2 */
    return single_rotate_with_right( k1 );
}

/*
    insert a new node into the tree
*/
node* insert(int e, node* t )
{
    if( t == NULL )
    {
        /* Create and return a one-node tree */
        t = (node*)malloc(sizeof(node));
        if( t == NULL )
        {
            fprintf (stderr, "Out of memory!!! (insert)\n");
            exit(1);
        }
        else
        {
            t->data = e;
            t->height = 0;
            t->left = t->right = NULL;
        }
    }
    else if( e < t->data )
    {
        t->left = insert( e, t->left );
        if( height( t->left ) - height( t->right ) == 2 )
            if( e < t->left->data )
                t = single_rotate_with_left( t );
            else
                t = double_rotate_with_left( t );
    }
    else if( e > t->data )
    {
        t->right = insert( e, t->right );
        if( height( t->right ) - height( t->left ) == 2 )
            if( e > t->right->data )
                t = single_rotate_with_right( t );
            else
                t = double_rotate_with_right( t );
    }
    /* Else X is in the tree already; we'll do nothing */

    t->height = max( height( t->left ), height( t->right ) ) + 1;
    return t;
}

/*
    remove a node in the tree
*/
node* delete( int e, node* t )
{
    printf( "Sorry; Delete is unimplemented; %d remains\n", e );
    return t;
}

/*
    data data of a node
*/
int get(node* n)
{
    return n->data;
}

/*
    Recursively display AVL tree or subtree
*/
void display_avl(node* t)
{
    if (t == NULL)
        return;
    printf("%d",t->data);

    if(t->left != NULL)
        printf("(L:%d)",t->left->data);
    if(t->right != NULL)
        printf("(R:%d)",t->right->data);
    printf("\n");

    display_avl(t->left);
    display_avl(t->right);
}
Code language: C++ (cpp)

Popularity 10/10 Helpfulness 1/10 Language cpp

Source: www.learnc.net

Tags: avl-tree avl-tre

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Contributed on Dec 22 2021

Vast Vicuña

0 Answers Avg Quality 2/10

avl tree

Comment

1

z                               z                           x
    / \                            /   \                        /  \ 
   y   T4  Left Rotate (y)        x    T4  Right Rotate(z)    y      z
  / \      - - - - - - - - ->    /  \      - - - - - - - ->  / \    / \
T1   x                          y    T3                    T1  T2 T3  T4
    / \                        / \
  T2   T3                    T1   T2

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Source: www.geeksforgeeks.org

Tags: avl-tree avl-tre

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Contributed on May 04 2022

Nethmi Mohotti

0 Answers Avg Quality 2/10

AVL trees

Comment

0

private void RightRotation(AVLTree<T> v){
    int BF_right = MAX_VALUE;

    if(v.getRight() != null){
        BF_right = v.getRight().getBF();
        if(BF_right == 1){
            RightLeft(v);
            RightRightRotate(v);
        }else if(BF_right <= 0){
            RightRightRotate(v);
        }
    }


}


private void RightLeft(AVLTree<T> v){
    AVLTree<T> v_right = null;
    AVLTree<T> v_right_left = null;
    AVLTree<T> v_right_left_right = null;
    if(v.right != null){
        v_right = v.right;
        v.right.height -=1;
        if(v.right.left != null){
            v.right.left.height +=1;
            v_right_left = v.right.left;
            if(v.right.left.right != null){
                v_right_left_right = v.right.left.right;
            }
        }
        v.left.right = v_right_left_right;
        v.left = v_right_left;
        v.left.left = v_right;
    }

}

    private void RightRightRotate(AVLTree<T> v){
        v.height -=2;
        AVLTree<T> v_right= null;
        AVLTree<T> v_right_left= null;
        AVLTree<T> v_right_right= null;

        if(v.right != null){
            v_right = v.right;
            if(v.right.left != null){
                v_right_left = v.right.left;
            }
            if(v.right.right != null){
                v_right_right = v.right.right;
            }
            AVLTree<T> new_v = new AVLTree<T>(v.val);
            new_v.right = v.right;
            new_v.left = v.left;
            v.left = new_v;
            v.val = v.right.val;
            v.left.right = v_right_left;
            v.right = v_right_right;


        }

    }

private void LeftRotation(AVLTree<T> v){
    int  BF_left = MAX_VALUE;
    if(v.getLeft() != null){
        BF_left = v.getLeft().getBF();
        if(BF_left == -1){
            leftRightRotate(v);
            leftLeftRotate(v);
        }else if (BF_left >= 0){
            leftLeftRotate(v);
        }
    }
}

private void leftLeftRotate(AVLTree<T> v){
        v.height -=2;
        AVLTree<T> v_left = null;
        AVLTree<T> v_left_right= null;
        AVLTree<T> v_left_left= null;

        if(v.left != null){
            v_left = v.left;
            if(v.left.right != null){
                v_left_right = v.left.right;
            }
            if(v.left.left != null){
                v_left_left = v.left.left;
            }
            AVLTree<T> new_v = new AVLTree<T>(v.val);
            new_v.left = v.left;
            new_v.right = v.right;
            v.right = new_v;
            v.val = v.left.val;
            v.right.left = v_left_right;
            v.left = v_left_left;


        }

    }
private void leftRightRotate(AVLTree<T> v){
    AVLTree<T> v_left = null;
    AVLTree<T> v_left_right = null;
    AVLTree<T> v_left_right_left = null;
    if(v.left != null){
        v_left = v.left;
        v.left.height -=1;
        if(v.left.right != null){
            v.left.right.height +=1;
            v_left_right = v.left.right;
            if(v.left.right.left != null){
                v_left_right_left = v.left.right.left;
            }
        }
        v.left.right = v_left_right_left;
        v.left = v_left_right;
        v.left.left = v_left;
    }


}

Popularity 10/10 Helpfulness 1/10 Language java

Source: Grepper

Tags: java

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Contributed on Dec 30 2022

Mero

0 Answers Avg Quality 2/10

avl tree c++

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0

Popularity 1/10 Helpfulness 1/10 Language cpp

Source: Grepper

Tags: avl-tree c++

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Contributed on Nov 22 2021

Ashamed Ape

0 Answers Avg Quality 2/10

AVL trees

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package il.ac.telhai.ds.trees;

public class AVLTree<T extends Comparable<T>>{
    private static final int MAX_VALUE = 999999999;
    public T val;
    public AVLTree<T> left;
    public AVLTree<T> right;
    public int height;


    //add the value to the tree, and return the updated root of the tree.
    public AVLTree(T value){
        this.val = value;
        left = null;
        right = null;
        height = 0;
    }

    //return the value in this node
    public T getValue(){
        return val;
    }

    //return the left subTree of this node
    public AVLTree<T> getLeft(){
        return left;
    }

    //return the right subTree of this node
    public AVLTree<T> getRight(){
        return right;
    }

    public  AVLTree<T> add(T val) {
        if(val == null) return null;
        if(this.val.compareTo(val) < 0){
            if(this.right == null){
                this.height += 1;
                this.right = new AVLTree<T>(val);
                return this;
            }
            this.height += 1;
            this.right = this.right.add(val);
        }else if(this.val.compareTo(val) > 0){
            if(this.left == null){
                this.height += 1;
                this.left = new AVLTree<T>(val);
                return this;
            }
            this.height += 1;
            this.left = this.left.add(val);
        }else{
            return null;
        }

        int V_BF = this.getBF();
        switch(V_BF){
            case 2:{
                LeftRotation(this);
                break;
            }
            case -2:{
                RightRotation(this);
                break;
            }

        }



        return this;
    }

    private int getBF(){
        return HackHeight(left) - HackHeight(right);
    }




private int GetHight(){
        return HackHeight(this);
}
    private int HackHeight(AVLTree<T> node){
        int lef=0,righ=0;
        if(node == null) return -1;
        lef= HackHeight(node.getLeft());
        righ= HackHeight(node.getRight());
        return Math.max(righ, lef)+1;
    }
}

Popularity 10/10 Helpfulness 1/10 Language java

Source: Grepper

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Contributed on Dec 30 2022

Mero

0 Answers Avg Quality 2/10

avl tree

Comment

0

z                               z                           x
    / \                            /   \                        /  \ 
   y   T4  Left Rotate (y)        x    T4  Right Rotate(z)    y      z
  / \      - - - - - - - - ->    /  \      - - - - - - - ->  / \    / \
T1   x                          y    T3                    T1  T2 T3  T4
    / \                        / \
  T2   T3                    T1   T2

Popularity 10/10 Helpfulness 1/10 Language whatever

Source: www.geeksforgeeks.org

Tags: avl-tree avl-tre

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Contributed on May 04 2022

Nethmi Mohotti

0 Answers Avg Quality 2/10

Avl Tree

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