Data Structures and Algorithm

2021-10-12 17:39:34 +05:30
parent 66d088557c
commit f7d245563b
3 changed files with 259 additions and 0 deletions
--- a/Java/data-structure-with-java/tree/avl/AVLTree.java
+++ b/Java/data-structure-with-java/tree/avl/AVLTree.java
@@ -0,0 +1,195 @@
+package tree.avl;
+
+class AVLTree{
+    private AVLNode root;
+    public AVLTree(){
+        root = null;
+    }
+
+
+    /**
+     *
+     * @param avlNode
+     * @return
+     */
+    private int height(AVLNode avlNode ){
+        return avlNode == null ? -1 : avlNode.height;
+    }
+
+    /**
+     *
+     * @param lHeight
+     * @param rHeight
+     * @return
+     */
+    private int max(int lHeight, int rHeight){
+        return lHeight > rHeight ? lHeight : rHeight;
+    }
+
+    /**
+     *
+     * @param data
+     */
+    public void insert(int data){
+        root = insert(data, root);
+    }
+
+
+    /**
+     *
+     * @param data
+     * @param avlNode
+     * @return
+     */
+    private AVLNode insert(int data, AVLNode avlNode)
+    {
+        if (avlNode == null)
+            avlNode = new AVLNode(data);
+        else if (data < avlNode.data){
+            avlNode.left = insert( data, avlNode.left );
+            if( height( avlNode.left ) - height( avlNode.right ) == 2 )
+                if( data < avlNode.left.data )
+                    avlNode = leftRotation( avlNode );
+                else
+                    avlNode = leftRightRotation( avlNode );
+        }
+        else if( data > avlNode.data ){
+            avlNode.right = insert( data, avlNode.right );
+            if( height( avlNode.right ) - height( avlNode.left ) == 2 )
+                if( data > avlNode.right.data)
+                    avlNode = rightRotation( avlNode );
+                else
+                    avlNode = rightLeftRotation( avlNode );
+        }
+        else
+            ;  // Duplicate; do nothing
+        avlNode.height = max( height( avlNode.left ), height( avlNode.right ) ) + 1;
+        return avlNode;
+    }
+
+    /**
+     *
+     * @param avlNode
+     * @return
+     */
+    private AVLNode leftRotation(AVLNode avlNode){
+        AVLNode k1 = avlNode.left;
+        avlNode.left = k1.right;
+        k1.right = avlNode;
+        avlNode.height = max( height( avlNode.left ), height( avlNode.right ) ) + 1;
+        k1.height = max( height( k1.left ), avlNode.height ) + 1;
+        return k1;
+    }
+
+
+    /**
+     *
+     * @param avlNode
+     * @return
+     */
+    private AVLNode rightRotation(AVLNode avlNode){
+        AVLNode node = avlNode.right;
+        avlNode.right = node.left;
+        node.left = avlNode;
+        avlNode.height = max( height( avlNode.left ), height( avlNode.right ) ) + 1;
+        node.height = max( height( node.right ), avlNode.height ) + 1;
+        return node;
+    }
+    /**
+     * left-right rotation
+     * @param avlNode
+     * @return
+     */
+    private AVLNode leftRightRotation(AVLNode avlNode){
+        avlNode.left = rightRotation( avlNode.left );
+        return leftRotation( avlNode );
+    }
+
+    /**
+     * right-left rotation
+     * @param avlNode
+     * @return
+     */
+    private AVLNode rightLeftRotation(AVLNode avlNode)
+    {
+        avlNode.right = leftRotation( avlNode.right );
+        return rightRotation( avlNode );
+    }
+
+    /**
+     *
+     * @return
+     */
+    public int countNodes(){
+        return countNodes(root);
+    }
+
+    /**
+     *
+     * @param avlNode
+     * @return
+     */
+    private int countNodes(AVLNode avlNode){
+        if (avlNode == null)
+            return 0;
+        else{
+            int l = 1;
+            l += countNodes(avlNode.left);
+            l += countNodes(avlNode.right);
+            return l;
+        }
+    }
+
+    /**
+     *
+     * @param data
+     * @return
+     */
+    public boolean search(int data){
+        return search(root, data);
+    }
+
+    /**
+     *
+     * @param avlNode
+     * @param data
+     * @return
+     */
+    private boolean search(AVLNode avlNode, int data){
+        boolean found = false;
+        while ((avlNode != null) && !found)
+        {
+            int rval = avlNode.data;
+            if (data < rval)
+                avlNode = avlNode.left;
+            else if (data > rval)
+                avlNode = avlNode.right;
+            else
+            {
+                found = true;
+                break;
+            }
+            found = search(avlNode, data);
+        }
+        return found;
+    }
+
+    /**
+     *
+     */
+    public void inorder(){
+        inorder(root);
+    }
+
+    /**
+     *
+     * @param avlNode
+     */
+    private void inorder(AVLNode avlNode){
+        if (avlNode != null){
+            inorder(avlNode.left);
+            System.out.print(avlNode.data +" ");
+            inorder(avlNode.right);
+        }
+    }
+}