Added notebook index. Added note about using additional data structures for the Pythonic solution. Minor cleanup.

arrays-strings/reverse_string.ipynb

@@ -4,7 +4,13 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## Problem: Implement the function void Reverse(char* str)"
+    "## Problem: Implement the function void Reverse(char* str)\n",
+    "\n",
+    "* [Clarifying Questions](#Clarifying-Questions)\n",
+    "* [Test Cases](#Test-Cases)\n",
+    "* [Algorithm](#Algorithm)\n",
+    "* [Code](#Code)\n",
+    "* [Pythonic-Code](#Pythonic-Code)"
    ]
   },
   {
@@ -26,8 +32,8 @@
     "## Test Cases\n",
     "\n",
     "* NULL input\n",
-    "* \"\" -> \"\"\n",
-    "* \"foo bar\" -> \"rab oof\""
+    "* '' -> ''\n",
+    "* 'foo bar' -> 'rab oof'"
    ]
   },
   {
@@ -36,7 +42,7 @@
    "source": [
     "## Algorithm\n",
     "\n",
-    "We'll want to keep two pointers\n",
+    "We'll want to keep two pointers:\n",
     "* i is a pointer to the first char\n",
     "* j is a pointer to the last char\n",
     "\n",
@@ -46,8 +52,8 @@
     "    * swap i and j\n",
     "\n",
     "Complexity:\n",
-    "* Time: O(n).\n",
-    "* Space: In-place.\n",
+    "* Time: O(n)\n",
+    "* Space: In-place\n",
     "\n",
     "Note:\n",
     "* Instead of using i, you can use str instead, although this might not be as intuitive."
@@ -111,7 +117,9 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## Pythonic Solution(s)"
+    "## Pythonic Code\n",
+    "\n",
+    "The following code is Pythonic, but requires using additional data structures as Python strings are immutable.  You could use a bytearray or a list instead of a string to simulate manipulating an array of characters."
    ]
   },
   {
@@ -126,7 +134,7 @@
     "    return string[::-1]\n",
     "\n",
     "def reverse_string_alt2(string):\n",
-    "    return \"\".join(reversed(string))"
+    "    return ''.join(reversed(string))"
    ]
   }
  ],