D              D
   /             /
  A   S   -->    A   S
     /              /
    N              N   Z
(size = 4)      (size = 5)

public static class BSTNode
{
    public BSTNode leftTree = null;
    public BSTNode rightTree = null;
    public int subtreeSize = 1;
    public int value;

    public BSTNode(int valToAdd){
        value = valToAdd;
    }
}

public static class BST
{
    public BSTNode root;

    //public void insert(int valToAdd)
}

public void insert(int valToAdd)
{
    if(root == null){
        root = new BSTNode(valToAdd);
        return;
    }

    BSTNode parent = root;
    BSTNode current = root;
    while(current != null){
        parent = current;
        ++current.subtreeSize;
        if(valToAdd <= current.value){
            current = current.leftTree;
        }
        else{
            current = current.rightTree;
        }
    }

    if(valToAdd <= parent.value){
        parent.leftTree = new BSTNode(valToAdd);
    }
    else{
        parent.rightTree = new BSTNode(valToAdd);
    }
}

public static class BSTNode
{
    public BSTNode leftTree = null;
    public BSTNode rightTree = null;
    public int height = 0;
    public int value;

    public BSTNode(int valToAdd){
        value = valToAdd;
    }
}

public void insert(int valToAdd)
{
    if(root == null){
        root = new BSTNode(valToAdd);
        return;
    }

    java.util.Stack<BSTNode> stack = new java.util.Stack<BSTNode>();

    BSTNode parent = root;
    BSTNode current = root;
    while(current != null){
        parent = current;
        stack.push(current);
        if(valToAdd <= current.value){
            current = current.leftTree;
        }
        else{
            current = current.rightTree;
        }
    }

    if(valToAdd <= parent.value){
        parent.leftTree = new BSTNode(valToAdd);
    }
    else{
        parent.rightTree = new BSTNode(valToAdd);
    }

    int height = 1;
    while(!stack.isEmpty()){
        current = stack.pop();
        current.height = Math.max(height, current.height);
        ++height;
    }
}