diff --git a/online_judges/merge_ranges/__init__.py b/online_judges/merge_ranges/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/online_judges/merge_ranges/merge_ranges_challenge.ipynb b/online_judges/merge_ranges/merge_ranges_challenge.ipynb
new file mode 100644
index 0000000..8f955e4
--- /dev/null
+++ b/online_judges/merge_ranges/merge_ranges_challenge.ipynb
@@ -0,0 +1,188 @@
+{
+ "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: Given a list of tuples representing ranges, condense the ranges. \n",
+ "\n",
+ "Example: [(2, 3), (3, 5), (7, 9), (8, 10)] -> [(2, 5), (7, 10)]\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",
+ "* Are the tuples in sorted order?\n",
+ " * No\n",
+ "* Are the tuples ints?\n",
+ " * Yes\n",
+ "* Will all tuples have the first element less than the second?\n",
+ " * Yes\n",
+ "* Is there an upper bound on the input range?\n",
+ " * No\n",
+ "* Is the output a list of tuples?\n",
+ " * Yes\n",
+ "* Is the output a new array?\n",
+ " * Yes\n",
+ "* Can we assume the inputs are valid?\n",
+ " * No, check for None\n",
+ "* Can we assume this fits memory?\n",
+ " * Yes"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Test Cases\n",
+ "\n",
+ "\n",
+ "* None input -> TypeError\n",
+ "* [] - []\n",
+ "* [(2, 3), (7, 9)] -> [(2, 3), (7, 9)]\n",
+ "* [(2, 3), (3, 5), (7, 9), (8, 10)] -> [(2, 5), (7, 10)]\n",
+ "* [(2, 3), (3, 5), (7, 9), (8, 10), (1, 11)] -> [(1, 11)]\n",
+ "* [(2, 3), (3, 8), (7, 9), (8, 10)] -> [(2, 10)]\n",
+ "
"
+ ]
+ },
+ {
+ "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 merge_ranges(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_merge_ranges.py\n",
+ "from nose.tools import assert_equal, assert_raises\n",
+ "\n",
+ "\n",
+ "class TestMergeRanges(object):\n",
+ "\n",
+ " def test_merge_ranges(self):\n",
+ " solution = Solution()\n",
+ " assert_raises(TypeError, solution.merge_ranges, None)\n",
+ " assert_equal(solution.merge_ranges([]), [])\n",
+ " array = [(2, 3), (7, 9)]\n",
+ " expected = [(2, 3), (7, 9)]\n",
+ " assert_equal(solution.merge_ranges(array), expected)\n",
+ " array = [(2, 3), (3, 5), (7, 9), (8, 10)]\n",
+ " expected = [(2, 5), (7, 10)]\n",
+ " assert_equal(solution.merge_ranges(array), expected)\n",
+ " array = [(2, 3), (3, 5), (7, 9), (8, 10), (1, 11)]\n",
+ " expected = [(1, 11)]\n",
+ " assert_equal(solution.merge_ranges(array), expected)\n",
+ " print('Success: test_merge_ranges')\n",
+ "\n",
+ "\n",
+ "def main():\n",
+ " test = TestMergeRanges()\n",
+ " test.test_merge_ranges()\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/merge_ranges/merge_ranges_solution.ipynb b/online_judges/merge_ranges/merge_ranges_solution.ipynb
new file mode 100644
index 0000000..584315a
--- /dev/null
+++ b/online_judges/merge_ranges/merge_ranges_solution.ipynb
@@ -0,0 +1,256 @@
+{
+ "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: Given a list of tuples representing ranges, condense the ranges. \n",
+ "\n",
+ "Example: [(2, 3), (3, 5), (7, 9), (8, 10)] -> [(2, 5), (7, 10)]\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",
+ "* Are the tuples in sorted order?\n",
+ " * No\n",
+ "* Are the tuples ints?\n",
+ " * Yes\n",
+ "* Will all tuples have the first element less than the second?\n",
+ " * Yes\n",
+ "* Is there an upper bound on the input range?\n",
+ " * No\n",
+ "* Is the output a list of tuples?\n",
+ " * Yes\n",
+ "* Is the output a new array?\n",
+ " * Yes\n",
+ "* Can we assume the inputs are valid?\n",
+ " * No, check for None\n",
+ "* Can we assume this fits memory?\n",
+ " * Yes"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Test Cases\n",
+ "\n",
+ "\n",
+ "* None input -> TypeError\n",
+ "* [] - []\n",
+ "* [(2, 3), (7, 9)] -> [(2, 3), (7, 9)]\n",
+ "* [(2, 3), (3, 5), (7, 9), (8, 10)] -> [(2, 5), (7, 10)]\n",
+ "* [(2, 3), (3, 5), (7, 9), (8, 10), (1, 11)] -> [(1, 11)]\n",
+ "* [(2, 3), (3, 8), (7, 9), (8, 10)] -> [(2, 10)]\n",
+ "
"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Algorithm\n",
+ "\n",
+ "* Sort the tuples based on start time\n",
+ "* Check each adjacent tuple to see if they can be merged\n",
+ "\n",
+ "\n",
+ "Case: * [(2, 3), (3, 8), (7, 9), (8, 10)] -> [(2, 10)]\n",
+ "\n",
+ "* Sort by start time (already sorted)\n",
+ "* Add the first tuple to the merged_array\n",
+ "* Loop through each item in sorted_array starting at index 1\n",
+ " * If there is no overlap\n",
+ " * Add the current item to merged_array\n",
+ " * Else\n",
+ " * Update the last item in merged_array\n",
+ " * The end time will be the max of merged_array[-1][1] and sorted_array[i][1]\n",
+ "\n",
+ "Start:\n",
+ " i\n",
+ " 0 1 2 3\n",
+ "sorted_array = [(2, 3), (3, 8), (7, 9), (8, 10)]\n",
+ "merged_array = [(2, 3)]\n",
+ "\n",
+ "Overlap with (2, 3), (3, 8):\n",
+ " i\n",
+ " 0 1 2 3\n",
+ "sorted_array = [(2, 3), (3, 8), (7, 9), (8, 10)]\n",
+ "merged_array = [(2, 8)]\n",
+ "\n",
+ "Overlap with (2, 8), (7, 9):\n",
+ " i\n",
+ " 0 1 2 3\n",
+ "sorted_array = [(2, 3), (3, 8), (7, 9), (8, 10)]\n",
+ "merged_array = [(2, 9)]\n",
+ "\n",
+ "Overlap with (2, 9) (8, 10):\n",
+ " i\n",
+ " 0 1 2 3\n",
+ "sorted_array = [(2, 3), (3, 8), (7, 9), (8, 10)]\n",
+ "merged_array = [(2, 10)]\n",
+ "
\n",
+ "\n",
+ "Complexity:\n",
+ "* Time: O(n log(n))\n",
+ "* Space: O(n)"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Code"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 1,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [],
+ "source": [
+ "class Solution(object):\n",
+ "\n",
+ " def merge_ranges(self, array):\n",
+ " if array is None:\n",
+ " raise TypeError('array cannot be None')\n",
+ " if not array:\n",
+ " return array\n",
+ " sorted_array = sorted(array)\n",
+ " merged_array = [sorted_array[0]]\n",
+ " for index, item in enumerate(sorted_array):\n",
+ " if index == 0:\n",
+ " continue\n",
+ " start_prev, end_prev = merged_array[-1]\n",
+ " start_curr, end_curr = item\n",
+ " if end_prev < start_curr:\n",
+ " # No overlap, add the entry\n",
+ " merged_array.append(item)\n",
+ " else:\n",
+ " # Overlap, update the previous entry's end value\n",
+ " merged_array[-1] = (start_prev, max(end_prev, end_curr))\n",
+ " return merged_array"
+ ]
+ },
+ {
+ "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_merge_ranges.py\n"
+ ]
+ }
+ ],
+ "source": [
+ "%%writefile test_merge_ranges.py\n",
+ "from nose.tools import assert_equal, assert_raises\n",
+ "\n",
+ "\n",
+ "class TestMergeRanges(object):\n",
+ "\n",
+ " def test_merge_ranges(self):\n",
+ " solution = Solution()\n",
+ " assert_raises(TypeError, solution.merge_ranges, None)\n",
+ " assert_equal(solution.merge_ranges([]), [])\n",
+ " array = [(2, 3), (7, 9)]\n",
+ " expected = [(2, 3), (7, 9)]\n",
+ " assert_equal(solution.merge_ranges(array), expected)\n",
+ " array = [(3, 5), (2, 3), (7, 9), (8, 10)]\n",
+ " expected = [(2, 5), (7, 10)]\n",
+ " assert_equal(solution.merge_ranges(array), expected)\n",
+ " array = [(2, 3), (3, 5), (7, 9), (8, 10), (1, 11)]\n",
+ " expected = [(1, 11)]\n",
+ " assert_equal(solution.merge_ranges(array), expected)\n",
+ " print('Success: test_merge_ranges')\n",
+ "\n",
+ "\n",
+ "def main():\n",
+ " test = TestMergeRanges()\n",
+ " test.test_merge_ranges()\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_merge_ranges\n"
+ ]
+ }
+ ],
+ "source": [
+ "%run -i test_merge_ranges.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/merge_ranges/test_merge_ranges.py b/online_judges/merge_ranges/test_merge_ranges.py
new file mode 100644
index 0000000..5d39cf2
--- /dev/null
+++ b/online_judges/merge_ranges/test_merge_ranges.py
@@ -0,0 +1,28 @@
+from nose.tools import assert_equal, assert_raises
+
+
+class TestMergeRanges(object):
+
+ def test_merge_ranges(self):
+ solution = Solution()
+ assert_raises(TypeError, solution.merge_ranges, None)
+ assert_equal(solution.merge_ranges([]), [])
+ array = [(2, 3), (7, 9)]
+ expected = [(2, 3), (7, 9)]
+ assert_equal(solution.merge_ranges(array), expected)
+ array = [(3, 5), (2, 3), (7, 9), (8, 10)]
+ expected = [(2, 5), (7, 10)]
+ assert_equal(solution.merge_ranges(array), expected)
+ array = [(2, 3), (3, 5), (7, 9), (8, 10), (1, 11)]
+ expected = [(1, 11)]
+ assert_equal(solution.merge_ranges(array), expected)
+ print('Success: test_merge_ranges')
+
+
+def main():
+ test = TestMergeRanges()
+ test.test_merge_ranges()
+
+
+if __name__ == '__main__':
+ main()
\ No newline at end of file