Question

Implement a method to build an AVL tree out of a sorted (ascending order) array of unique integers, with the fastest possible big O running time. You may implement private helper methods as necessary. If your code builds a tree that is other than an AVL tree, you will not get any credit. If your code builds an AVL tree, but is not the fastest big O implementation, you will get at most 12 points. You may use any of the Math class methods (max, min, abs, etc.) as needed.

Hint: Given that the input array is sorted, think of how you might build the tree without doing any rotations.

public class AVLTreeNode {

    public int key;

    public AVLTreeNode left, right;

    public char balanceFactor; // ‘/’, ‘\’, or ‘-‘

    public AVLTreeNode(key, left, right) {

        this.key = key;

        this.left = left;

        this.right = right;

        height = 0;

        balanceFactor = ‘-‘;

    }

}

// builds an AVL tree out of a sorted array of integer keys,

// returns the root of the tree, null if array is empty

public static AVLTreeNode buildAVLTree(int[] arr) {

    // COMPLETE THIS METHOD

}

Answer 1

Public state Avl TreeNode bulld Avl Tree (int[Jarr) { return build Avl Tree Helper/arr, o, arr.length-1); private static Avl TreeNode build Ave Tree Helper (intarr [] int start, int end) { if (start>end) return null; intmid= (start tend) 12; AVL TreeNode node = new Avl Tree Nodelarr (mid), null, null); node.left= build Avl Tree Helper (arr, stort, mid-1); node.right=build Avl Tree Helper (arr, mid+ 1, end); return node;