      "\n",
      "* 5, 2, 8, 1, 3 -> 1, 2, 3, 5, 8\n",
      "* 1, 2, 3, 4, 5 -> 1, 2, 3, 4, 5\n",
      "\n",
      "If the `root` input is `None`, return a tree with the only element being the new root node."
     ]
    },
    {
     "cell_type": "markdown",
     "metadata": {},
 
</s>
    "If the `root` input is `None`, return a tree with the only element being the new root node.\n",
    "\n",
    "You do not have to code the in-order traversal, it is part of the unit test."
      "\n",
      "* 5, 2, 8, 1, 3 -> 1, 2, 3, 5, 8\n",
      "* 1, 2, 3, 4, 5 -> 1, 2, 3, 4, 5\n",
      "\n",
    "If the `root` input is `None`, return a tree with the only element being the new root node.\n",
    "\n",
    "You do not have to code the in-order traversal, it is part of the unit test."
     ]
    },
    {
     "cell_type": "markdown",
     "metadata": {},
keep keep keep keep replace keep keep keep keep keep
 Polish bst challenge and solution (#75)

Update constraints, algorithm discussion, and code.
graphs_trees/bst/bst_solution.ipynb