      "* Recursively call in-order traversal on the right child\n",
      "\n",
      "Complexity:\n",
      "* Time: O(n)\n",
      "* Space: O(h), where h is the height of the tree\n",
      "\n",
      "Note:\n",
      "* This is a form of a depth-first traversal\n",
      "\n",
      "### Pre-Order Traversal\n",
 
</s> remove     "* Space: O(h), where h is the height of the tree\n",
 </s> add     "* Space: O(m), where m is the recursion depth, or O(1) if using an iterative approach\n", </s> remove     "* Space: O(h), where h is the height of the tree\n",
 </s> add     "* Space: O(m), where m is the recursion depth, or O(1) if using an iterative approach\n", </s> remove    "pygments_lexer": "ipython2",
   "version": "2.7.10"
 </s> add    "pygments_lexer": "ipython3",
   "version": "3.4.3" </s> remove     "version": 2
 </s> add     "version": 3 </s> remove    "name": "python2"
 </s> add    "name": "python3"
    "* Space: O(m), where m is the recursion depth, or O(1) if using an iterative approach\n",
      "* Recursively call in-order traversal on the right child\n",
      "\n",
      "Complexity:\n",
      "* Time: O(n)\n",
    "* Space: O(m), where m is the recursion depth, or O(1) if using an iterative approach\n",
      "\n",
      "Note:\n",
      "* This is a form of a depth-first traversal\n",
      "\n",
      "### Pre-Order Traversal\n",
keep keep keep keep replace keep keep keep keep keep
 Update dfs solution complexity discussion 
graphs_trees/tree_dfs/dfs_solution.ipynb