Fixed pull request changes

README.md

@@ -216,7 +216,7 @@ Challenges, solutions, and unit tests are presented in the form of **IPython/Jup
 | Print all valid combinations of n-pairs of parentheses | [Contribute](https://github.com/donnemartin/interactive-coding-challenges/blob/master/CONTRIBUTING.md)│[Contribute](https://github.com/donnemartin/interactive-coding-challenges/blob/master/CONTRIBUTING.md) |
 | Implement a paint fill function | [Contribute](https://github.com/donnemartin/interactive-coding-challenges/blob/master/CONTRIBUTING.md)│[Contribute](https://github.com/donnemartin/interactive-coding-challenges/blob/master/CONTRIBUTING.md) |
 | Find all permutations to represent n cents, given 1, 5, 10, 25 cent coins | [Contribute](https://github.com/donnemartin/interactive-coding-challenges/blob/master/CONTRIBUTING.md)│[Contribute](https://github.com/donnemartin/interactive-coding-challenges/blob/master/CONTRIBUTING.md) |
-| Find the number of ways to represent n cents given k arbitrary cent coins | [Challenge](http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/recursion_dynamic/coin_change_ways/coinchange_ways_challenge.ipynb)│[Solution](http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/recursion_dynamic/coin_change_ways/coinchange_ways_solution.ipynb) |
+| Find the number of ways to represent n cents given an array of coins | [Challenge](http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/recursion_dynamic/coin_change_ways/coinchange_ways_challenge.ipynb)│[Solution](http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/recursion_dynamic/coin_change_ways/coinchange_ways_solution.ipynb) |
 | Add a challenge | [Contribute](https://github.com/donnemartin/interactive-coding-challenges/blob/master/CONTRIBUTING.md)│[Contribute](https://github.com/donnemartin/interactive-coding-challenges/blob/master/CONTRIBUTING.md) |
 
 <br/>

recursion_dynamic/coinchange_ways/coinchange_ways_challenge.ipynb

@@ -34,9 +34,9 @@
    "source": [
     "## Explanation\n",
     "\n",
-    "How many ways are there of making change for n, given k distinct coins? For example:\n",
+    "How many ways are there of making change for n, given an array of distinct coins? For example:\n",
     "\n",
-    "Input: n = 4, k = 2, coins = [1,2]\n",
+    "Input: n = 4, coins = [1, 2]\n",
     "\n",
     "Output: 3. 1+1+1+1, 1+2+1, 2+2, would be the ways of making change.\n",
     "\n",
@@ -49,9 +49,9 @@
    "source": [
     "## Test Cases\n",
     "\n",
-    "* Input: n = 0, k = 2, coins = [1,2] -> Output: 0\n",
+    "* Input: n = 0, coins = [1, 2] -> Output: 0\n",
-    "* Input: n = 100, k = 3, coins = [1,2,3] -> Output: 884\n",
+    "* Input: n = 100, coins = [1, 2, 3] -> Output: 884\n",
-    "* Input: n = 1000, k = 100, coins = [1,2,3...99,100] -> Output: 15658181104580771094597751280645\n"
+    "* Input: n = 1000, coins = [1, 2, 3...99, 100] -> Output: 15658181104580771094597751280645\n"
    ]
   },
   {
@@ -78,7 +78,7 @@
    },
    "outputs": [],
    "source": [
-    "def change_ways(n,k,coins):\n",
+    "def change_ways(n, coins):\n",
     "    # TODO: Implement me\n",
     "    return n"
    ]
@@ -115,9 +115,9 @@
     "class Challenge(object):\n",
     "\n",
     "    def test_coinchange_ways(self,solution):\n",
-    "        assert_equal(solution(0,2,[1,2]), 0)\n",
+    "        assert_equal(solution(0, [1, 2]), 0)\n",
-    "        assert_equal(solution(100,3,[1,2,3]), 884)\n",
+    "        assert_equal(solution(100, [1, 2, 3]), 884)\n",
-    "        assert_equal(solution(1000,100,range(1,101)), 15658181104580771094597751280645)\n",
+    "        assert_equal(solution(1000, range(1, 101)), 15658181104580771094597751280645)\n",
     "        print('Success: test_coinchange_ways')\n",
     "\n",
     "\n",

recursion_dynamic/coinchange_ways/coinchange_ways_solution.ipynb

@@ -54,7 +54,7 @@
     "* We are essentially adding the coin we are iterating on to the # of ways of making arr[i].\n",
     "\n",
     "Complexity:\n",
-    "* Time: O(mn)\n",
+    "* Time: O(mn); let the number of coins be m. We iterate from arr[coin] -> arr[n], or ~ n operations on each coin, hence n*m. \n",
     "* Space: O(n)"
    ]
   },
@@ -73,10 +73,10 @@
    },
    "outputs": [],
    "source": [
-    "def change_ways(n,k,coins):\n",
+   "def change_ways(n, coins):\n",
    "    arr = [1] + [0] * n\n",
    "    for coin in coins:\n",
-    "        for i in xrange(coin,n + 1):\n",
+   "        for i in range(coin, n + 1):\n",
    "            arr[i] += arr[i - coin]\n",
    "    return 0 if n == 0 else arr[n]"
    ]
@@ -112,9 +112,9 @@
     "class Challenge(object):\n",
     "\n",
     "    def test_coinchange_ways(self,solution):\n",
-    "        assert_equal(solution(0,2,[1,2]), 0)\n",
+    "        assert_equal(solution(0, [1, 2]), 0)\n",
-    "        assert_equal(solution(100,3,[1,2,3]), 884)\n",
+    "        assert_equal(solution(100, [1, 2, 3]), 884)\n",
-    "        assert_equal(solution(1000,100,range(1,101)), 15658181104580771094597751280645)\n",
+    "        assert_equal(solution(1000, range(1, 101)), 15658181104580771094597751280645)\n",
     "        print('Success: test_coinchange_ways')\n",
     "\n",
     "\n",

recursion_dynamic/coinchange_ways/test_coinchange_ways.py

@@ -4,9 +4,9 @@ from nose.tools import assert_equal
 class Challenge(object):
 
     def test_coinchange_ways(self,solution):
-        assert_equal(solution(0,2,[1,2]), 0)
+        assert_equal(solution(0, [1, 2]), 0)
-        assert_equal(solution(100,3,[1,2,3]), 884)
+        assert_equal(solution(100, [1, 2, 3]), 884)
-        assert_equal(solution(1000,100,range(1,101)), 15658181104580771094597751280645)
+        assert_equal(solution(1000, range(1, 101)), 15658181104580771094597751280645)
         print('Success: test_coinchange_ways')