Added the set solution for str_diff_solution

arrays_strings/str_diff/str_diff_solution.ipynb

@@ -31,7 +31,7 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "## Constraints\n",
+    "# Constraints\n",
     "\n",
     "* Can we assume the strings are ASCII?\n",
     "    * Yes\n",
@@ -76,6 +76,15 @@
     "\n",
     "Complexity:\n",
     "* Time: O(m+n), where m and n are the lengths of s, t\n",
+    "* Space: O(1)\n",
+    "\n",
+    "### Set - Difference\n",
+    "\n",
+    "* A set is an unordered collection of unique elements.\n",
+    "    * Return a string of a new set with an element in set(t) that is not in set(s).\n",
+    "\n",
+    "Complexity:\n",
+    "* Time: O(m+n), where m and n are the lengths of s, t\n",
     "* Space: O(1)"
    ]
   },
@@ -88,7 +97,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 1,
+   "execution_count": 19,
    "metadata": {
     "collapsed": false
    },
@@ -122,7 +131,13 @@
     "            result ^= ord(char)\n",
     "        for char in str2:\n",
     "            result ^= ord(char)\n",
-    "        return chr(result)"
+    "        return chr(result)\n",
+    "\n",
+    "    def find_diff_set(self, str1, str2):\n",
+    "        if str1 is None or str2 is None:\n",
+    "            raise TypeError('str1 or str2 cannot be None')\n",
+    "        else:\n",
+    "            return ''.join(set(str2) - set(str1))"
    ]
   },
   {
@@ -134,7 +149,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 2,
+   "execution_count": 20,
    "metadata": {
     "collapsed": false
    },
@@ -173,7 +188,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 3,
+   "execution_count": 21,
    "metadata": {
     "collapsed": false
    },
@@ -192,10 +207,11 @@
   }
  ],
  "metadata": {
+  "anaconda-cloud": {},
   "kernelspec": {
-   "display_name": "Python 3",
+   "display_name": "Python [Root]",
    "language": "python",
-   "name": "python3"
+   "name": "Python [Root]"
   },
   "language_info": {
    "codemirror_mode": {
@@ -207,7 +223,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.5.0"
+   "version": "3.5.2"
   }
  },
  "nbformat": 4,