From ebd2701a3f2d170dc9658cf80b7a9c9e5df5f4e9 Mon Sep 17 00:00:00 2001
From: justani98 <justani98@gmail.com>
Date: Mon, 3 Jul 2017 10:41:25 +0530
Subject: [PATCH 1/6] Implement exercise change


From 3a9688a89afc152816374bbdb1d73b3c79825a01 Mon Sep 17 00:00:00 2001
From: justani98 <justani98@gmail.com>
Date: Mon, 3 Jul 2017 15:32:48 +0530
Subject: [PATCH 2/6] Add new entry in config.json file for the exercise change

---
 config.json | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/config.json b/config.json
index fafc965c010..a8b1c57612b 100644
--- a/config.json
+++ b/config.json
@@ -565,6 +565,15 @@
         "strings",
         "pattern matching"
       ]
+    },
+    {
+      "slug": "change",
+      "difficulty": 4,
+      "topics": [
+        "Control-flow (loops)",
+        "Arrays",
+        "Algorithms"
+      ]
     }
   ],
   "deprecated": [

From 48217ce45b4855ea833f57ea1802243fe7a9c3fc Mon Sep 17 00:00:00 2001
From: justani98 <justani98@gmail.com>
Date: Mon, 3 Jul 2017 16:11:47 +0530
Subject: [PATCH 3/6] Add change.py

---
 exercises/change/change.py | 2 ++
 1 file changed, 2 insertions(+)
 create mode 100644 exercises/change/change.py

diff --git a/exercises/change/change.py b/exercises/change/change.py
new file mode 100644
index 00000000000..88b882e1632
--- /dev/null
+++ b/exercises/change/change.py
@@ -0,0 +1,2 @@
+def find_minimum_coins(total_change, coins):
+    pass

From cb30deb662a0ca34f459a6ac63fdddfec762f4f6 Mon Sep 17 00:00:00 2001
From: justani98 <justani98@gmail.com>
Date: Mon, 3 Jul 2017 16:12:20 +0530
Subject: [PATCH 4/6] Add example.py

---
 exercises/change/example.py | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 exercises/change/example.py

diff --git a/exercises/change/example.py b/exercises/change/example.py
new file mode 100644
index 00000000000..bbe5c92957a
--- /dev/null
+++ b/exercises/change/example.py
@@ -0,0 +1,23 @@
+def find_minimum_coins(total_change, coins):
+    min_coins_required = [1e9] * (total_change + 1)
+    last_coin = [0]*(total_change + 1)
+    min_coins_required[0] = 0
+    last_coin[0] = -1
+    for change in range(1, total_change + 1):
+        final_result = min_coins_required[change]
+        for coin in coins:
+            if coin <= change:
+                result = min_coins_required[change - coin] + 1
+                if result < final_result:
+                    final_result = result
+                    last_coin[change] = change - coin
+        min_coins_required[change] = final_result
+    if min_coins_required[total_change] == 1e9:
+        return -1
+    else:
+        last_coin_value = total_change
+        array = []
+        while(last_coin[last_coin_value] != -1):
+            array.append(last_coin_value-last_coin[last_coin_value])
+            last_coin_value = last_coin[last_coin_value]
+        return array

From bf89ae4cd3a6edd89d570bdc5f2f0d01fc9a5620 Mon Sep 17 00:00:00 2001
From: justani98 <justani98@gmail.com>
Date: Mon, 3 Jul 2017 16:49:37 +0530
Subject: [PATCH 5/6] Modify example.py for a test case

---
 exercises/change/example.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/exercises/change/example.py b/exercises/change/example.py
index bbe5c92957a..895145fe575 100644
--- a/exercises/change/example.py
+++ b/exercises/change/example.py
@@ -1,4 +1,6 @@
 def find_minimum_coins(total_change, coins):
+    if total_change < 0:
+        return -1
     min_coins_required = [1e9] * (total_change + 1)
     last_coin = [0]*(total_change + 1)
     min_coins_required[0] = 0

From 35ec8892cba71f4b987d9c0d8094fc40d850376a Mon Sep 17 00:00:00 2001
From: justani98 <justani98@gmail.com>
Date: Mon, 3 Jul 2017 16:50:16 +0530
Subject: [PATCH 6/6] Add test file

---
 exercises/change/change_test.py | 43 +++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 exercises/change/change_test.py

diff --git a/exercises/change/change_test.py b/exercises/change/change_test.py
new file mode 100644
index 00000000000..3f89363331c
--- /dev/null
+++ b/exercises/change/change_test.py
@@ -0,0 +1,43 @@
+import unittest
+
+from change import find_minimum_coins
+
+
+class ChangeTest(unittest.TestCase):
+    def test_single_coin_change(self):
+        self.assertEqual(find_minimum_coins(25, [1, 5, 10, 25, 100]), [25])
+
+    def test_multiple_coin_change(self):
+        self.assertEqual(find_minimum_coins(15, [1, 5, 10, 25, 100]), [5, 10])
+
+    def test_change_with_Lilliputian_Coins(self):
+        self.assertEqual(find_minimum_coins(23, [1, 4, 15, 20, 50]),
+                         [4, 4, 15])
+
+    def test_change_with_Lower_Elbonia_Coins(self):
+        self.assertEqual(find_minimum_coins(63, [1, 5, 10, 21, 25]),
+                         [21, 21, 21])
+
+    def test_large_target_values(self):
+        self.assertEqual(find_minimum_coins(21, [2, 5, 10, 20, 50]),
+                         [2, 2, 2, 5, 10])
+
+    def test_possible_change_without_unit_coins_available(self):
+        self.assertEqual(find_minimum_coins(21, [2, 5, 10, 20, 50]),
+                         [2, 2, 2, 5, 10])
+
+    def test_no_coins_make_0_change(self):
+        self.assertEqual(find_minimum_coins(0, [1, 5, 10, 21, 25]), [])
+
+    def test_error_testing_for_change_smaller_than_smallest_coin(self):
+        self.assertEqual(find_minimum_coins(3, [5, 10]), -1)
+
+    def test_error_if_no_combination_can_add_up_to_target(self):
+        self.assertEqual(find_minimum_coins(94, [5, 10]), -1)
+
+    def test_cannot_find_negative_change_values(self):
+        self.assertEqual(find_minimum_coins(-5, [1, 2, 5]), -1)
+
+
+if __name__ == "__main__":
+    unittest.main()