Method commonAncestor

java/Chapter 4/Question4_7/QuestionB.java:25–30

(TreeNode root, TreeNode p, TreeNode q)

	}
	
	public static TreeNode commonAncestor(TreeNode root, TreeNode p, TreeNode q) {
		if (!covers(root, p) || !covers(root, q)) { // Error check - one node is not in tree
			return null;
		}
		return commonAncestorHelper(root, p, q);
	}	
	
	public static void main(String[] args) {
		int[] array = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};