From 73d265525bd4fea84a353a3ebbeb5d919d8d61bf Mon Sep 17 00:00:00 2001
From: Donne Martin <donne.martin@gmail.com>
Date: Thu, 21 May 2015 06:05:32 -0400
Subject: [PATCH] Added notebook solving the following: HackerRank Maximizing
 XOR problem..

---
 README.md                        |  1 +
 hacker-rank/maximizing-xor.ipynb | 85 ++++++++++++++++++++++++++++++++
 2 files changed, 86 insertions(+)
 create mode 100644 hacker-rank/maximizing-xor.ipynb

diff --git a/README.md b/README.md
index 94fd5d8..76bad2f 100644
--- a/README.md
+++ b/README.md
@@ -42,6 +42,7 @@ Continually updated IPython Notebooks containing coding problems and solutions (
 ## Hacker Rank
 
 * [Utopian Tree](http://nbviewer.ipython.org/github/donnemartin/algorithms-data-structures/blob/master/hacker-rank/utopian-tree.ipynb)
+* [Maximizing XOR](http://nbviewer.ipython.org/github/donnemartin/algorithms-data-structures/blob/master/hacker-rank/maximizing-xor.ipynb)
 
 ## License
 
diff --git a/hacker-rank/maximizing-xor.ipynb b/hacker-rank/maximizing-xor.ipynb
new file mode 100644
index 0000000..2ef336a
--- /dev/null
+++ b/hacker-rank/maximizing-xor.ipynb
@@ -0,0 +1,85 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Problem: Maximizing XOR\n",
+    "\n",
+    "From HackerRank: https://www.hackerrank.com/challenges/maximizing-xor\n",
+    "\n",
+    "* [Algorithm](#Algorithm)\n",
+    "* [Code](#Code)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Algorithm\n",
+    "\n",
+    "* Set max to 0\n",
+    "* For i in the range (lower, upper) inclusive\n",
+    "    * For j in the range (lower, upper) inclusive\n",
+    "        * Compare i ^ j with max, update max if needed\n",
+    "* return max\n",
+    "\n",
+    "Complexity:\n",
+    "* Time: O(n^2)\n",
+    "* Space: O(1)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Code"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "def max_xor(lower, upper):\n",
+    "    result = 0\n",
+    "    for l in xrange(lower, upper + 1):\n",
+    "        for u in xrange(lower, upper + 1):\n",
+    "            curr = l ^ u\n",
+    "            if result < curr:\n",
+    "                result = curr\n",
+    "    return result\n",
+    "\n",
+    "lower = int(raw_input());\n",
+    "upper = int(raw_input());\n",
+    "\n",
+    "result = max_xor(lower, upper);\n",
+    "print(result)"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 2",
+   "language": "python",
+   "name": "python2"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 2
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython2",
+   "version": "2.7.9"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}