// Zorah Fung, CSE 143
// An IntTree object represents an entire binary tree of ints.

public class IntTree {
    private IntTreeNode overallRoot;

    // Constructs an empty binary tree.
    public IntTree() {
        overallRoot = null;
    }

    // Constructs a binary tree with the given node as its root.
    // Note: this is hacky and just useful for testing
    public IntTree(IntTreeNode root) {
        overallRoot = root;
    }

    // Prints a pre-order traversal of this tree.
    public void printPreorder() {
        printPreorder(overallRoot);
    }

    // Prints a pre-order traversal of the tree starting at the given root
    private void printPreorder(IntTreeNode root) {
        // implicit base case: do nothing when we reach a null root
        if (root != null) {
            System.out.print(root.data + " ");
            printPreorder(root.left);
            printPreorder(root.right);
        }
    }

    // Prints an in-order traversal of this tree.
    public void printInorder() {
        printInorder(overallRoot);
    }

    // Prints an in-order traversal of the tree starting at the given root
    private void printInorder(IntTreeNode root) {
        if (root != null) {
            printInorder(root.left);
            System.out.print(root.data + " ");
            printInorder(root.right);
        }
    }

    // Prints a post-order traversal of this tree.
    public void printPostorder() {
        printPostorder(overallRoot);
    }

    // Prints a post-order traversal of the tree starting at the given root
    private void printPostorder(IntTreeNode root) {
        if (root != null) {
            printPostorder(root.left);
            printPostorder(root.right);
            System.out.print(root.data + " ");
        }
    }
    
    // Returns the number of elements in this tree.
    public int size() {
        return size(overallRoot);
    }
    
    // Returns the number of elements in the tree at the given root.
    private int size(IntTreeNode root) {
        if (root == null) {
            return 0;
        } else {
            return size(root.left) + size(root.right) + 1;
        }
    }
}