private static BinarySearchTree ConstructSampleBSTWithParentPointer() { var tree = new BinarySearchTree(); tree.InsertWithParentPointerUpdated(5); tree.InsertWithParentPointerUpdated(3); tree.InsertWithParentPointerUpdated(1); tree.InsertWithParentPointerUpdated(4); tree.InsertWithParentPointerUpdated(6); return tree; }