{"preorder":[1, 2, 4, 7, 5, 3, 6, 8, 9],
"inorder":[7, 4, 2, 5, 1, 8, 6, 9, 3],
"postorder":[7, 4, 5, 2, 8, 9, 6, 3, 1],
"level-order":[1, 2, 3, 4, 5, 6, 7, 8, 9]}