AVLDeclaration.java: Add AVL Tree DS

Closes NITSkmOS#49

README.md

@@ -27,6 +27,7 @@ This repository contains examples of various algorithms written on different pro
 |:----------------------------------------------------------------------------------------------- |:-------------------------------------:|:-------------------------------------:|:-------------------------------------:|:-------------------------------------:|
 | [Queue](https://en.wikipedia.org/wiki/Queue_(abstract_data_type))                               |                                       | [:octocat:](queue/Cpp)                |                                       |                                       |
 | [Linear Linked List](https://en.wikipedia.org/wiki/Linked_list)                                 | [:octocat:](linked_list/C)            |                                       |                                       |                                       |
+| [AVL Tree](https://en.wikipedia.org/wiki/AVL_tree)                                              |                                       | [:octocat:](avl_tree/Java)            |                                       |                                       |
 
 
 ## Sample Run

avl_tree/Java/AVLDeclaration.java

@@ -0,0 +1,53 @@
+public class AVLDeclaration {
+    private int data;
+    private int height;
+    private AVLDeclaration left;
+    private AVLDeclaration right;
+
+    public AVLDeclaration(int data) {
+        this.data = data;
+    }
+
+    public int getData() {
+        return data;
+    }
+
+    public void setData(int data){
+        this.data = data;
+    }
+
+    public void setHeigth(int height){
+        this.height = height;
+    }
+
+    public int getHeight() {
+        return height;
+    }
+
+    public AVLDeclaration getleft() {
+        return left;
+    }
+
+    public void setleft(AVLDeclaration left) {
+        this.left = left;
+    }
+
+    public AVLDeclaration getright() {
+        return right;
+    }
+
+    public void setRight(AVLDeclaration left) {
+        this.right = right;
+    }
+
+
+    @Override
+    public String toString() {
+        return "AVLDeclaration{" +
+                "data=" + data +
+                ", height=" + height +
+                ", left=" + left +
+                ", right=" + right +
+                '}';
+    }
+}

avl_tree/Java/main.java

@@ -0,0 +1,94 @@
+public class AVLOPERATONS {
+    public static void main(String[] args) {
+        AVLDeclaration root = new AVLDeclaration(56);
+        AVLDeclaration left1 = new AVLDeclaration(48);
+        AVLDeclaration right1 = new AVLDeclaration(59);
+        AVLDeclaration left12 = new AVLDeclaration(32);
+        AVLDeclaration right12 = new AVLDeclaration(50);
+        AVLDeclaration right11 = new AVLDeclaration(60);
+        AVLDeclaration right111 = new AVLDeclaration(62);
+
+        root.setHeigth(1);
+        root.setleft(left1);
+        root.setRight(right1);
+        left1.setleft(left12);
+        left1.setRight(right12);
+        right1.setRight(right11);
+        right1.setHeigth(2);
+        right11.setRight(right111);
+        right11.setHeigth(2);
+        right111.setHeigth(3);
+        left1.setHeigth(2);
+        left12.setHeigth(2);
+        right12.setHeigth(3);
+    }
+
+    public  int height(AVLDeclaration root){
+        if(root == null)
+            return -1;
+        else
+            return root.getHeight();
+    }
+
+
+    public AVLDeclaration leftLeftRotation(AVLDeclaration x){
+        AVLDeclaration w = x.getleft();
+        x.setleft(w.getright());
+        w.setRight(x);
+        x.setHeigth(Math.max(height(x.getleft()),height(x.getright()))+1);
+        w.setHeigth(Math.max(height(w.getleft()),height(x))+1);
+
+        return w;
+    }
+
+    public AVLDeclaration rightRightRotation(AVLDeclaration x){
+        AVLDeclaration w = x.getright();
+        x.setRight(w.getleft());
+        w.setleft(x);
+        x.setHeigth(Math.max(height(x.getleft()),height(x.getright()))+1);
+        w.setHeigth(Math.max(height(w.getright()),height(x))+1);
+
+        return w;
+    }
+
+    public AVLDeclaration leftRightrotation(AVLDeclaration z){
+        z.setleft(rightRightRotation(z.getleft()));
+        return leftLeftRotation(z);
+    }
+
+    public AVLDeclaration rightLeftRotation(AVLDeclaration z){
+        z.setRight(leftLeftRotation(z.getright()));
+        return rightRightRotation(z);
+    }
+
+
+    public AVLDeclaration insert(AVLDeclaration root, AVLDeclaration parent, int data){
+        if(root == null){
+            root = new AVLDeclaration(data);
+            root.setHeigth(0);
+            root.setleft(null);
+            root.setRight(null);
+        }
+        else if(data < root.getData()){
+            root.setleft(insert(root.getleft(), root, data));
+            if(height(root.getleft()) - height(root.getright()) == 2){
+                if(data < root.getleft().getData())
+                    root = leftLeftRotation(root);
+                else
+                    root = leftRightrotation(root);
+            }
+        }
+        else if(data > root.getData()){
+            root.setRight(insert(root.getright(), root, data));
+            if(height(root.getright()) - height(root.getleft()) == 2){
+                if(data < root.getright().getData())
+                    root = rightRightRotation(root);
+                else
+                    root = rightLeftRotation(root);
+            }
+        }
+        root.setHeigth(Math.max(height(root.getleft()), height(root.getright())) + 1);
+        return root;
+    }
+
+}