diff --git a/online_judges/prod_three/__init__.py b/online_judges/prod_three/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/online_judges/prod_three/prod_three_challenge.ipynb b/online_judges/prod_three/prod_three_challenge.ipynb
new file mode 100644
index 0000000..3c5f157
--- /dev/null
+++ b/online_judges/prod_three/prod_three_challenge.ipynb
@@ -0,0 +1,171 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "This notebook was prepared by [Donne Martin](https://github.com/donnemartin). Source and license info is on [GitHub](https://github.com/donnemartin/interactive-coding-challenges)."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Challenge Notebook"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Problem: Find the highest product of three numbers in a list.\n",
+    "\n",
+    "* [Constraints](#Constraints)\n",
+    "* [Test Cases](#Test-Cases)\n",
+    "* [Algorithm](#Algorithm)\n",
+    "* [Code](#Code)\n",
+    "* [Unit Test](#Unit-Test)\n",
+    "* [Solution Notebook](#Solution-Notebook)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Constraints\n",
+    "\n",
+    "* Is the input a list of integers?\n",
+    "    * Yes\n",
+    "* Can we get negative inputs?\n",
+    "    * Yes\n",
+    "* Can there be duplicate entires in the input?\n",
+    "    * Yes\n",
+    "* Will there always be at least three integers?\n",
+    "    * No\n",
+    "* Can we assume the inputs are valid?\n",
+    "    * No, check for None input\n",
+    "* Can we assume this fits memory?\n",
+    "    * Yes"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Test Cases\n",
+    "\n",
+    "* None -> TypeError\n",
+    "* Less than three ints -> ValueError\n",
+    "* [5, -2, 3] -> -30\n",
+    "* [5, -2, 3, 1, -1, 4] -> 60"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Algorithm\n",
+    "\n",
+    "Refer to the [Solution Notebook]().  If you are stuck and need a hint, the solution notebook's algorithm discussion might be a good place to start."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Code"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "class Solution(object):\n",
+    "\n",
+    "    def max_prod_three(self, array):\n",
+    "        # TODO: Implement me\n",
+    "        pass"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Unit Test"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "**The following unit test is expected to fail until you solve the challenge.**"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "# %load test_prod_three.py\n",
+    "from nose.tools import assert_equal, assert_raises\n",
+    "\n",
+    "\n",
+    "class TestProdThree(object):\n",
+    "\n",
+    "    def test_prod_three(self):\n",
+    "        solution = Solution()\n",
+    "        assert_raises(TypeError, solution.max_prod_three, None)\n",
+    "        assert_raises(ValueError, solution.max_prod_three, [1, 2])\n",
+    "        assert_equal(solution.max_prod_three([5, -2, 3]), -30)\n",
+    "        assert_equal(solution.max_prod_three([5, -2, 3, 1, -1, 4]), 60)\n",
+    "        print('Success: test_prod_three')\n",
+    "\n",
+    "\n",
+    "def main():\n",
+    "    test = TestProdThree()\n",
+    "    test.test_prod_three()\n",
+    "\n",
+    "\n",
+    "if __name__ == '__main__':\n",
+    "    main()"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Solution Notebook\n",
+    "\n",
+    "Review the [Solution Notebook]() for a discussion on algorithms and code solutions."
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.5.0"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/online_judges/prod_three/prod_three_solution.ipynb b/online_judges/prod_three/prod_three_solution.ipynb
new file mode 100644
index 0000000..e79c333
--- /dev/null
+++ b/online_judges/prod_three/prod_three_solution.ipynb
@@ -0,0 +1,279 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "This notebook was prepared by [Donne Martin](https://github.com/donnemartin). Source and license info is on [GitHub](https://github.com/donnemartin/interactive-coding-challenges)."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Solution Notebook"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Problem: Find the highest product of three numbers in a list.\n",
+    "\n",
+    "* [Constraints](#Constraints)\n",
+    "* [Test Cases](#Test-Cases)\n",
+    "* [Algorithm](#Algorithm)\n",
+    "* [Code](#Code)\n",
+    "* [Unit Test](#Unit-Test)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Constraints\n",
+    "\n",
+    "* Is the input a list of integers?\n",
+    "    * Yes\n",
+    "* Can we get negative inputs?\n",
+    "    * Yes\n",
+    "* Can there be duplicate entires in the input?\n",
+    "    * Yes\n",
+    "* Will there always be at least three integers?\n",
+    "    * No\n",
+    "* Can we assume the inputs are valid?\n",
+    "    * No, check for None input\n",
+    "* Can we assume this fits memory?\n",
+    "    * Yes"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Test Cases\n",
+    "\n",
+    "* None -> TypeError\n",
+    "* Less than three ints -> ValueError\n",
+    "* [5, -2, 3] -> -30\n",
+    "* [5, -2, 3, 1, -1, 4] -> 60"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Algorithm\n",
+    "\n",
+    "### Brute force:\n",
+    "\n",
+    "Use three loops and multiple each numbers.\n",
+    "\n",
+    "Complexity:\n",
+    "* Time: O(n^3)\n",
+    "* Space: O(1)\n",
+    "\n",
+    "### Sorting:\n",
+    "\n",
+    "Sort the list, multiply the last three elements.\n",
+    "\n",
+    "Complexity:\n",
+    "* Time: O(n log(n))\n",
+    "* Space: O(1)\n",
+    "\n",
+    "### Greedy:\n",
+    "\n",
+    "<pre>\n",
+    " 0   1  2  3   4  5\n",
+    "[5, -2, 3, 1, -1, 4] -> 60\n",
+    "\n",
+    "max_prod_of_three = -30\n",
+    "max_prod_of_two = -10\n",
+    "max_num = 5\n",
+    "min_prod_of_two = -10\n",
+    "min_num = -2\n",
+    "\n",
+    " 0   1  2  3   4  5\n",
+    "[5, -2, 3, 1, -1, 4] -> 60\n",
+    "        ^\n",
+    "max_prod_of_three = -30\n",
+    "max_prod_of_two = 15\n",
+    "max_num = 5\n",
+    "min_prod_of_two = -10\n",
+    "min_num = -2\n",
+    "\n",
+    " 0   1  2  3   4  5\n",
+    "[5, -2, 3, 1, -1, 4] -> 60\n",
+    "           ^\n",
+    "max_prod_of_three = 15\n",
+    "max_prod_of_two = 15\n",
+    "max_num = 5\n",
+    "min_prod_of_two = -10\n",
+    "min_num = -2\n",
+    "\n",
+    " 0   1  2  3   4  5\n",
+    "[5, -2, 3, 1, -1, 4] -> 60\n",
+    "               ^\n",
+    "max_prod_of_three = 15\n",
+    "max_prod_of_two = 15\n",
+    "max_num = 5\n",
+    "min_prod_of_two = -10\n",
+    "min_num = -2\n",
+    "\n",
+    " 0   1  2  3   4  5\n",
+    "[5, -2, 3, 1, -1, 4] -> 60\n",
+    "                  ^\n",
+    "max_prod_of_three = 60\n",
+    "max_prod_of_two = 15\n",
+    "max_num = 5\n",
+    "min_prod_of_two = -10\n",
+    "min_num = -2\n",
+    "</pre>\n",
+    "\n",
+    "Complexity:\n",
+    "* Time: O(n)\n",
+    "* Space: O(1)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Code"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [],
+   "source": [
+    "class Solution(object):\n",
+    "\n",
+    "    def max_prod_three_nlogn(self, array):\n",
+    "        if array is None:\n",
+    "            raise TypeError('array cannot be None')\n",
+    "        if len(array) < 3:\n",
+    "            raise ValueError('array must have 3 or more ints')\n",
+    "        array.sort()\n",
+    "        product = 1\n",
+    "        for item in array[-3:]:\n",
+    "            product *= item\n",
+    "        return product\n",
+    "\n",
+    "    def max_prod_three(self, array):\n",
+    "        if array is None:\n",
+    "            raise TypeError('array cannot be None')\n",
+    "        if len(array) < 3:\n",
+    "            raise ValueError('array must have 3 or more ints')\n",
+    "        curr_max_prod_three = array[0] * array[1] * array[2]\n",
+    "        max_prod_two = array[0] * array[1]\n",
+    "        min_prod_two = array[0] * array[1]\n",
+    "        max_num = max(array[0], array[1])\n",
+    "        min_num = min(array[0], array[1])\n",
+    "        for i in range(2, len(array)):\n",
+    "            curr_max_prod_three = max(curr_max_prod_three,\n",
+    "                                      max_prod_two * array[i],\n",
+    "                                      min_prod_two * array[i])\n",
+    "            max_prod_two = max(max_prod_two,\n",
+    "                               max_num * array[i],\n",
+    "                               min_num * array[i])\n",
+    "            min_prod_two = min(min_prod_two,\n",
+    "                               max_num * array[i],\n",
+    "                               min_num * array[i])\n",
+    "            max_num = max(max_num, array[i])\n",
+    "            min_num = min(min_num, array[i])\n",
+    "        return curr_max_prod_three"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Unit Test"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 2,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Overwriting test_prod_three.py\n"
+     ]
+    }
+   ],
+   "source": [
+    "%%writefile test_prod_three.py\n",
+    "from nose.tools import assert_equal, assert_raises\n",
+    "\n",
+    "\n",
+    "class TestProdThree(object):\n",
+    "\n",
+    "    def test_prod_three(self):\n",
+    "        solution = Solution()\n",
+    "        assert_raises(TypeError, solution.max_prod_three, None)\n",
+    "        assert_raises(ValueError, solution.max_prod_three, [1, 2])\n",
+    "        assert_equal(solution.max_prod_three([5, -2, 3]), -30)\n",
+    "        assert_equal(solution.max_prod_three([5, -2, 3, 1, -1, 4]), 60)\n",
+    "        print('Success: test_prod_three')\n",
+    "\n",
+    "\n",
+    "def main():\n",
+    "    test = TestProdThree()\n",
+    "    test.test_prod_three()\n",
+    "\n",
+    "\n",
+    "if __name__ == '__main__':\n",
+    "    main()"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 3,
+   "metadata": {
+    "collapsed": false
+   },
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Success: test_prod_three\n"
+     ]
+    }
+   ],
+   "source": [
+    "%run -i test_prod_three.py"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.4.3"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/online_judges/prod_three/test_prod_three.py b/online_judges/prod_three/test_prod_three.py
new file mode 100644
index 0000000..bbe5ccd
--- /dev/null
+++ b/online_judges/prod_three/test_prod_three.py
@@ -0,0 +1,21 @@
+from nose.tools import assert_equal, assert_raises
+
+
+class TestProdThree(object):
+
+    def test_prod_three(self):
+        solution = Solution()
+        assert_raises(TypeError, solution.max_prod_three, None)
+        assert_raises(ValueError, solution.max_prod_three, [1, 2])
+        assert_equal(solution.max_prod_three([5, -2, 3]), -30)
+        assert_equal(solution.max_prod_three([5, -2, 3, 1, -1, 4]), 60)
+        print('Success: test_prod_three')
+
+
+def main():
+    test = TestProdThree()
+    test.test_prod_three()
+
+
+if __name__ == '__main__':
+    main()
\ No newline at end of file