JAVA : Recursively complete the IsPerfectlyBalancedS method using one helper function for a binary tree.

public class MyIntSET {

private Node root;

private static class Node {

public final int key;

public Node left, right;

public Node(int key) { this.key = key; }

}

// tree is perfect if for every node, size of left == size of right

// hint: in the helper, return -1 if the tree is not perfect, otherwise return the size

public boolean isPerfectlyBalancedS() {

return false;

}