     "source": [
      "## Constraints\n",
      "\n",
      "* Can we assume we already have a Node class with an insert method?\n",
      "    * Yes"
     ]
    },
    {
     "cell_type": "markdown",
     "metadata": {},
 
</s>
    "    * Yes\n",
    "* Can we assume this fits in memory?\n",
    "    * Yes\n",
    "* What should we do with each node when we process it?\n",
    "    * Call an input method `visit_func` on the node"
     "source": [
      "## Constraints\n",
      "\n",
      "* Can we assume we already have a Node class with an insert method?\n",
    "    * Yes\n",
    "* Can we assume this fits in memory?\n",
    "    * Yes\n",
    "* What should we do with each node when we process it?\n",
    "    * Call an input method `visit_func` on the node"
     ]
    },
    {
     "cell_type": "markdown",
     "metadata": {},
keep keep keep keep replace keep keep keep keep keep
 Polish tree bfs challenge and solution (#77)

Update constraints and algorithm discussion.
graphs_trees/tree_bfs/bfs_solution.ipynb