Refactored test cases, tests are now called for all three algorithms. Tweaked algorithm description for in-place approach.

arrays-strings/unique_chars.ipynb

@@ -79,11 +79,23 @@
    "outputs": [],
    "source": [
     "def unique_chars(string):\n",
-    "    return len(set(string)) == len(string)\n",
+    "    return len(set(string)) == len(string)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "def test():\n",
+    "    print(unique_chars(''))\n",
+    "    print(unique_chars('foo'))\n",
+    "    print(unique_chars('bar'))\n",
     "\n",
-    "print(unique_chars(''))\n",
+    "test()"
-    "print(unique_chars('foo'))\n",
-    "print(unique_chars('bar'))"
    ]
   },
   {
@@ -132,7 +144,9 @@
     "            return False\n",
     "        else:\n",
     "            chars_set.add(char)\n",
-    "    return True"
+    "    return True\n",
+    "\n",
+    "test()"
    ]
   },
   {
@@ -141,7 +155,7 @@
    "source": [
     "## Algorithm 3: In-Place\n",
     "\n",
-    "Since we cannot use additional data structures, this will eliminate the fast lookup O(1) time provided by our hash map.\n",
+    "Assume we cannot use additional data structures, which will eliminate the fast lookup O(1) time provided by our hash map.  \n",
     "* Scan each character\n",
     "* For each character:\n",
     "    * Scan all [other] characters in the array\n",
@@ -173,7 +187,9 @@
     "    for char in string:\n",
     "        if string.count(char) > 1:\n",
     "            return False\n",
-    "    return True"
+    "    return True\n",
+    "\n",
+    "test()"
    ]
   }
  ],