diff --git a/recursion_dynamic/n_pairs_parentheses/__init__.py b/recursion_dynamic/n_pairs_parentheses/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/recursion_dynamic/n_pairs_parentheses/n_pairs_parentheses_challenge.ipynb b/recursion_dynamic/n_pairs_parentheses/n_pairs_parentheses_challenge.ipynb
index ac96f04..f7a3e77 100644
--- a/recursion_dynamic/n_pairs_parentheses/n_pairs_parentheses_challenge.ipynb
+++ b/recursion_dynamic/n_pairs_parentheses/n_pairs_parentheses_challenge.ipynb
@@ -18,7 +18,7 @@
"cell_type": "markdown",
"metadata": {},
"source": [
- "## Problem: Print all valid combinations of n-pairs of parentheses.\n",
+ "## Problem: Find all valid combinations of n-pairs of parentheses.\n",
"\n",
"* [Constraints](#Constraints)\n",
"* [Test Cases](#Test-Cases)\n",
@@ -33,7 +33,17 @@
"metadata": {},
"source": [
"## Constraints\n",
- "* None"
+ "\n",
+ "* Is the input an integer representing the number of pairs?\n",
+ " * Yes\n",
+ "* Can we assume the inputs are valid?\n",
+ " * No\n",
+ "* Is the output a list of valid combinations?\n",
+ " * Yes\n",
+ "* Should the output have duplicates?\n",
+ " * No\n",
+ "* Can we assume this fits memory?\n",
+ " * Yes"
]
},
{
@@ -42,10 +52,14 @@
"source": [
"## Test Cases\n",
"\n",
+ "\n",
+ "* None -> Exception\n",
+ "* Negative -> Exception\n",
"* 0 -> []\n",
- "* 1 -> [()]\n",
- "* 2 -> [(()), ()()]\n",
- "* 3 -> [((())), (()()), (())(), ()(()), ()()()]"
+ "* 1 -> ['()']\n",
+ "* 2 -> ['(())', '()()']\n",
+ "* 3 -> ['((()))', '(()())', '(())()', '()(())', '()()()']\n",
+ ""
]
},
{
@@ -72,17 +86,11 @@
},
"outputs": [],
"source": [
- "def parentheses_util(no_left, no_right, pair_string, result):\n",
- " # TODO: implement parentheses pairing here\n",
- " pass\n",
+ "class Parentheses(object):\n",
"\n",
- "\n",
- "def pair_parentheses(n):\n",
- " result_set = set()\n",
- " if n == 0:\n",
- " return result_set\n",
- " parentheses_util(n, n, '', result_set)\n",
- " return result_set"
+ " def find_pair(self, num_pairs):\n",
+ " # TODO: implement me\n",
+ " pass"
]
},
{
@@ -101,27 +109,30 @@
"outputs": [],
"source": [
"# %load test_n_pairs_parentheses.py\n",
- "from nose.tools import assert_equal\n",
+ "from nose.tools import assert_equal, assert_raises\n",
"\n",
"\n",
"class TestPairParentheses(object):\n",
"\n",
- " def test_pair_parentheses(self, solution):\n",
- " assert_equal(solution(0), set([]))\n",
- " assert_equal(solution(1), set(['()']))\n",
- " assert_equal(solution(2), set(['(())', \n",
- " '()()']))\n",
- " assert_equal(solution(3), set(['((()))', \n",
- " '(()())', \n",
- " '(())()', \n",
- " '()(())', \n",
- " '()()()']))\n",
+ " def test_pair_parentheses(self):\n",
+ " parentheses = Parentheses()\n",
+ " assert_raises(TypeError, parentheses.find_pair, None)\n",
+ " assert_raises(ValueError, parentheses.find_pair, -1)\n",
+ " assert_equal(parentheses.find_pair(0), [])\n",
+ " assert_equal(parentheses.find_pair(1), ['()'])\n",
+ " assert_equal(parentheses.find_pair(2), ['(())',\n",
+ " '()()'])\n",
+ " assert_equal(parentheses.find_pair(3), ['((()))',\n",
+ " '(()())',\n",
+ " '(())()',\n",
+ " '()(())',\n",
+ " '()()()'])\n",
" print('Success: test_pair_parentheses')\n",
"\n",
"\n",
"def main():\n",
" test = TestPairParentheses()\n",
- " test.test_pair_parentheses(pair_parentheses)\n",
+ " test.test_pair_parentheses()\n",
"\n",
"\n",
"if __name__ == '__main__':\n",
@@ -136,34 +147,25 @@
"\n",
"Review the [Solution Notebook](http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/recursion_dynamic/n_pairs_parentheses/n_pairs_parentheses_solution.ipynb) for a discussion on algorithms and code solutions."
]
- },
- {
- "cell_type": "code",
- "execution_count": null,
- "metadata": {
- "collapsed": true
- },
- "outputs": [],
- "source": []
}
],
"metadata": {
"kernelspec": {
- "display_name": "Python 2",
+ "display_name": "Python 3",
"language": "python",
- "name": "python2"
+ "name": "python3"
},
"language_info": {
"codemirror_mode": {
"name": "ipython",
- "version": 2
+ "version": 3
},
"file_extension": ".py",
"mimetype": "text/x-python",
"name": "python",
"nbconvert_exporter": "python",
- "pygments_lexer": "ipython2",
- "version": "2.7.10"
+ "pygments_lexer": "ipython3",
+ "version": "3.5.0"
}
},
"nbformat": 4,
diff --git a/recursion_dynamic/n_pairs_parentheses/n_pairs_parentheses_solution.ipynb b/recursion_dynamic/n_pairs_parentheses/n_pairs_parentheses_solution.ipynb
index c7ddd1a..a122861 100644
--- a/recursion_dynamic/n_pairs_parentheses/n_pairs_parentheses_solution.ipynb
+++ b/recursion_dynamic/n_pairs_parentheses/n_pairs_parentheses_solution.ipynb
@@ -18,7 +18,7 @@
"cell_type": "markdown",
"metadata": {},
"source": [
- "## Problem: Print all valid combinations of n-pairs of parentheses.\n",
+ "## Problem: Find all valid combinations of n-pairs of parentheses.\n",
"\n",
"* [Constraints](#Constraints)\n",
"* [Test Cases](#Test-Cases)\n",
@@ -32,7 +32,17 @@
"metadata": {},
"source": [
"## Constraints\n",
- "* None"
+ "\n",
+ "* Is the input an integer representing the number of pairs?\n",
+ " * Yes\n",
+ "* Can we assume the inputs are valid?\n",
+ " * No\n",
+ "* Is the output a list of valid combinations?\n",
+ " * Yes\n",
+ "* Should the output have duplicates?\n",
+ " * No\n",
+ "* Can we assume this fits memory?\n",
+ " * Yes"
]
},
{
@@ -41,10 +51,14 @@
"source": [
"## Test Cases\n",
"\n",
- "* 0 -> ' '\n",
- "* 1 -> ()\n",
- "* 2 -> (()), ()()\n",
- "* 3 -> ((())), (()()), (())(), ()(()), ()()()"
+ "\n",
+ "* None -> Exception\n",
+ "* Negative -> Exception\n",
+ "* 0 -> []\n",
+ "* 1 -> ['()']\n",
+ "* 2 -> ['(())', '()()']\n",
+ "* 3 -> ['((()))', '(()())', '(())()', '()(())', '()()()']\n",
+ "
"
]
},
{
@@ -64,14 +78,14 @@
" - Add the string generated to the result set\n",
"* Case 1: `l > 0`\n",
" - Add a left parenthesis to the parentheses string.\n",
- " - Call parentheses_util(l - 1, r, new_string, result_set)\n",
+ " - Recurse (l - 1, r, new_string, result_set)\n",
"* Case 2: `r > l`\n",
" - Add a right parenthesis to the parentheses string.\n",
- " - Call parentheses_util(l, r - 1, new_string, result_set)\n",
+ " - Recurse (l, r - 1, new_string, result_set)\n",
"\n",
"Complexity:\n",
- "* Time: `O(4^n/n^(3/2))`. See [Catalan numbers](https://en.wikipedia.org/wiki/Catalan_number#Applications_in_combinatorics)\n",
- "* Space complexity: `O(n)` (Due to the implicit call stack storing a maximum of 2n function calls)"
+ "* Time: `O(4^n/n^(3/2))`, see [Catalan numbers](https://en.wikipedia.org/wiki/Catalan_number#Applications_in_combinatorics) - 1, 1, 2, 5, 14, 42, 132...\n",
+ "* Space complexity: `O(n)`, due to the implicit call stack storing a maximum of 2n function calls)"
]
},
{
@@ -89,22 +103,28 @@
},
"outputs": [],
"source": [
- "def parentheses_util(no_left, no_right, pair_string, result):\n",
- " if no_left == 0 and no_right == 0:\n",
- " result.add(pair_string)\n",
- " else:\n",
- " if no_left > 0:\n",
- " parentheses_util(no_left - 1, no_right, pair_string + '(', result)\n",
- " if no_right > no_left:\n",
- " parentheses_util(no_left, no_right - 1, pair_string + ')', result)\n",
+ "class Parentheses(object):\n",
"\n",
+ " def find_pair(self, num_pairs):\n",
+ " if num_pairs is None:\n",
+ " raise TypeError('num_pairs cannot be None')\n",
+ " if num_pairs < 0:\n",
+ " raise ValueError('num_pairs cannot be < 0')\n",
+ " if not num_pairs:\n",
+ " return []\n",
+ " results = []\n",
+ " curr_results = []\n",
+ " self._find_pair(num_pairs, num_pairs, curr_results, results)\n",
+ " return results\n",
"\n",
- "def pair_parentheses(n):\n",
- " result_set = set()\n",
- " if n == 0:\n",
- " return result_set\n",
- " parentheses_util(n, n, '', result_set)\n",
- " return result_set"
+ " def _find_pair(self, nleft, nright, curr_results, results):\n",
+ " if nleft == 0 and nright == 0:\n",
+ " results.append(''.join(curr_results))\n",
+ " else:\n",
+ " if nleft >= 0:\n",
+ " self._find_pair(nleft-1, nright, curr_results+['('], results)\n",
+ " if nright > nleft:\n",
+ " self._find_pair(nleft, nright-1, curr_results+[')'], results)"
]
},
{
@@ -131,27 +151,30 @@
],
"source": [
"%%writefile test_n_pairs_parentheses.py\n",
- "from nose.tools import assert_equal\n",
+ "from nose.tools import assert_equal, assert_raises\n",
"\n",
"\n",
"class TestPairParentheses(object):\n",
"\n",
- " def test_pair_parentheses(self, solution):\n",
- " assert_equal(solution(0), set([]))\n",
- " assert_equal(solution(1), set(['()']))\n",
- " assert_equal(solution(2), set(['(())', \n",
- " '()()']))\n",
- " assert_equal(solution(3), set(['((()))', \n",
- " '(()())', \n",
- " '(())()', \n",
- " '()(())', \n",
- " '()()()']))\n",
+ " def test_pair_parentheses(self):\n",
+ " parentheses = Parentheses()\n",
+ " assert_raises(TypeError, parentheses.find_pair, None)\n",
+ " assert_raises(ValueError, parentheses.find_pair, -1)\n",
+ " assert_equal(parentheses.find_pair(0), [])\n",
+ " assert_equal(parentheses.find_pair(1), ['()'])\n",
+ " assert_equal(parentheses.find_pair(2), ['(())',\n",
+ " '()()'])\n",
+ " assert_equal(parentheses.find_pair(3), ['((()))',\n",
+ " '(()())',\n",
+ " '(())()',\n",
+ " '()(())',\n",
+ " '()()()'])\n",
" print('Success: test_pair_parentheses')\n",
"\n",
"\n",
"def main():\n",
" test = TestPairParentheses()\n",
- " test.test_pair_parentheses(pair_parentheses)\n",
+ " test.test_pair_parentheses()\n",
"\n",
"\n",
"if __name__ == '__main__':\n",
@@ -180,21 +203,21 @@
],
"metadata": {
"kernelspec": {
- "display_name": "Python 2",
+ "display_name": "Python 3",
"language": "python",
- "name": "python2"
+ "name": "python3"
},
"language_info": {
"codemirror_mode": {
"name": "ipython",
- "version": 2
+ "version": 3
},
"file_extension": ".py",
"mimetype": "text/x-python",
"name": "python",
"nbconvert_exporter": "python",
- "pygments_lexer": "ipython2",
- "version": "2.7.10"
+ "pygments_lexer": "ipython3",
+ "version": "3.5.0"
}
},
"nbformat": 4,
diff --git a/recursion_dynamic/n_pairs_parentheses/test_n_pairs_parentheses.py b/recursion_dynamic/n_pairs_parentheses/test_n_pairs_parentheses.py
index 1b735e8..8c2ab34 100644
--- a/recursion_dynamic/n_pairs_parentheses/test_n_pairs_parentheses.py
+++ b/recursion_dynamic/n_pairs_parentheses/test_n_pairs_parentheses.py
@@ -1,24 +1,27 @@
-from nose.tools import assert_equal
+from nose.tools import assert_equal, assert_raises
class TestPairParentheses(object):
- def test_pair_parentheses(self, solution):
- assert_equal(solution(0), set([]))
- assert_equal(solution(1), set(['()']))
- assert_equal(solution(2), set(['(())',
- '()()']))
- assert_equal(solution(3), set(['((()))',
- '(()())',
- '(())()',
- '()(())',
- '()()()']))
+ def test_pair_parentheses(self):
+ parentheses = Parentheses()
+ assert_raises(TypeError, parentheses.find_pair, None)
+ assert_raises(ValueError, parentheses.find_pair, -1)
+ assert_equal(parentheses.find_pair(0), [])
+ assert_equal(parentheses.find_pair(1), ['()'])
+ assert_equal(parentheses.find_pair(2), ['(())',
+ '()()'])
+ assert_equal(parentheses.find_pair(3), ['((()))',
+ '(()())',
+ '(())()',
+ '()(())',
+ '()()()'])
print('Success: test_pair_parentheses')
def main():
test = TestPairParentheses()
- test.test_pair_parentheses(pair_parentheses)
+ test.test_pair_parentheses()
if __name__ == '__main__':