Method commonAncestor

java/Chapter 4/Question4_7/QuestionC.java:46–52

(TreeNode root, TreeNode p, TreeNode q)

	}	
	
	public static TreeNode commonAncestor(TreeNode root, TreeNode p, TreeNode q) {
		Result r = commonAncestorHelper(root, p, q);
		if (r.isAncestor) {
			return r.node;
		}
		return null;
	}	
	
	public static void main(String[] args) {
		int[] array = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};