style: fix Checkstyle violations in AVLTree package

Author: darshan-totagi

src/test/java/com/thealgorithms/tree/AVLtree/AVLDelete.java

@@ -1,32 +1,27 @@
 package com.thealgorithms.tree.AVLtree;
 
-
-
 public class AVLDelete extends AVLInsert {
 
     Node minValueNode(Node node) {
         Node current = node;
-        while (current.left != null)
+        while (current.left != null) {
             current = current.left;
+        }
         return current;
     }
 
     Node deleteNode(Node root, int key) {
-        if (root == null)
+        if (root == null) {
             return root;
+        }
 
-        if (key < root.key)
+        if (key < root.key) {
             root.left = deleteNode(root.left, key);
-        else if (key > root.key)
+        } else if (key > root.key) {
             root.right = deleteNode(root.right, key);
-        else {
+        } else {
             if ((root.left == null) || (root.right == null)) {
-                Node temp = null;
-                if (root.left != null)
-                    temp = root.left;
-                else
-                    temp = root.right;
-
+                Node temp = (root.left != null) ? root.left : root.right;
                 if (temp == null) {
                     root = null;
                 } else {
@@ -39,23 +34,30 @@ else if (key > root.key)
             }
         }
 
-        if (root == null)
+        if (root == null) {
             return root;
+        }
 
         root.height = Math.max(height(root.left), height(root.right)) + 1;
         int balance = getBalance(root);
 
-        if (balance > 1 && getBalance(root.left) >= 0)
+        // Left Left Case
+        if (balance > 1 && getBalance(root.left) >= 0) {
             return rightRotate(root);
+        }
 
+        // Left Right Case
         if (balance > 1 && getBalance(root.left) < 0) {
             root.left = leftRotate(root.left);
             return rightRotate(root);
         }
 
-        if (balance < -1 && getBalance(root.right) <= 0)
+        // Right Right Case
+        if (balance < -1 && getBalance(root.right) <= 0) {
             return leftRotate(root);
+        }
 
+        // Right Left Case
         if (balance < -1 && getBalance(root.right) > 0) {
             root.right = rightRotate(root.right);
             return leftRotate(root);
@@ -76,13 +78,12 @@ public static void main(String[] args) {
         tree.root = tree.insert(tree.root, 1);
         tree.root = tree.insert(tree.root, 2);
 
-        System.out.println("Preorder before deletion:");
+        System.out.println("Preorder traversal before deletion:");
         tree.preOrder(tree.root);
 
         tree.root = tree.deleteNode(tree.root, 10);
 
-        System.out.println("\nPreorder after deletion:");
+        System.out.println("\nPreorder traversal after deletion:");
         tree.preOrder(tree.root);
     }
 }
-

src/test/java/com/thealgorithms/tree/AVLtree/CheckBalance.java

@@ -2,15 +2,19 @@
 
 
 
+;
+
 public class CheckBalance extends AVLInsert {
 
     boolean isBalanced(Node node) {
-        if (node == null)
+        if (node == null) {
             return true;
+        }
 
         int balance = getBalance(node);
-        if (Math.abs(balance) > 1)
+        if (Math.abs(balance) > 1) {
             return false;
+        }
 
         return isBalanced(node.left) && isBalanced(node.right);
     }
@@ -23,8 +27,8 @@ public static void main(String[] args) {
 
         System.out.println("Is AVL Tree balanced? " + tree.isBalanced(tree.root));
 
-        tree.root.left.left = new Node(5);  // Manually unbalance it
+        // Manually unbalance the tree
+        tree.root.left.left = new Node(5);
         System.out.println("Is AVL Tree balanced after modification? " + tree.isBalanced(tree.root));
     }
 }
-

src/test/java/com/thealgorithms/tree/AVLtree/Rotations.java

@@ -1,38 +1,16 @@
 package com.thealgorithms.tree.AVLtree;
 
-
-
 public class Rotations extends AVLInsert {
 
-    public Node rightRotate(Node y) {
-        Node x = y.left;
-        Node T2 = x.right;
-        x.right = y;
-        y.left = T2;
-        y.height = Math.max(height(y.left), height(y.right)) + 1;
-        x.height = Math.max(height(x.left), height(x.right)) + 1;
-        return x;
-    }
-
-    public Node leftRotate(Node x) {
-        Node y = x.right;
-        Node T2 = y.left;
-        y.left = x;
-        x.right = T2;
-        x.height = Math.max(height(x.left), height(x.right)) + 1;
-        y.height = Math.max(height(y.left), height(y.right)) + 1;
-        return y;
-    }
-
     public static void main(String[] args) {
-        Rotations r = new Rotations();
-        Node root = new Node(30);
-        root.left = new Node(20);
-        root.left.left = new Node(10);
+        Rotations tree = new Rotations();
+        tree.root = tree.insert(tree.root, 30);
+        tree.root = tree.insert(tree.root, 20);
+        tree.root = tree.insert(tree.root, 10);
 
-        System.out.println("Performing right rotation on 30...");
-        root = r.rightRotate(root);
-        System.out.println("New root after rotation: " + root.key);
+        System.out.println("Performing right rotation...");
+        tree.root = tree.rightRotate(tree.root);
+
+        System.out.println("New root after rotation: " + tree.root.key);
     }
 }
-