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authorVincent Ambo <mail@tazj.in>2021-12-13T22·51+0300
committerVincent Ambo <mail@tazj.in>2021-12-13T23·15+0300
commit019f8fd2113df4c5247c3969c60fd4f0e08f91f7 (patch)
tree76a857f61aa88f62a30e854651e8439db77fd0ea /users/wpcarro/scratch/data_structures_and_algorithms/coins.py
parent464bbcb15c09813172c79820bcf526bb10cf4208 (diff)
parent6123e976928ca3d8d93f0b2006b10b5f659eb74d (diff)
subtree(users/wpcarro): docking briefcase at '24f5a642' r/3226
git-subtree-dir: users/wpcarro
git-subtree-mainline: 464bbcb15c09813172c79820bcf526bb10cf4208
git-subtree-split: 24f5a642af3aa1627bbff977f0a101907a02c69f
Change-Id: I6105b3762b79126b3488359c95978cadb3efa789
Diffstat (limited to 'users/wpcarro/scratch/data_structures_and_algorithms/coins.py')
-rw-r--r--users/wpcarro/scratch/data_structures_and_algorithms/coins.py57
1 files changed, 57 insertions, 0 deletions
diff --git a/users/wpcarro/scratch/data_structures_and_algorithms/coins.py b/users/wpcarro/scratch/data_structures_and_algorithms/coins.py
new file mode 100644
index 000000000000..eb5754f98210
--- /dev/null
+++ b/users/wpcarro/scratch/data_structures_and_algorithms/coins.py
@@ -0,0 +1,57 @@
+import unittest
+from math import floor
+
+################################################################################
+# Solution
+################################################################################
+
+# change_possibilities :: Int -> [Int] -> Int
+def change_possibilities(n, xs):
+    combinations = [0] * (n + 1)
+    combinations[0] = 1
+
+    for x in xs:
+        for i in range(len(combinations)):
+            if i >= x:
+                combinations[i] += combinations[i - x]
+
+    return combinations[n]
+
+
+################################################################################
+# Tests
+################################################################################
+class Test(unittest.TestCase):
+
+    def test_sample_input(self):
+        actual = change_possibilities(4, (1, 2, 3))
+        expected = 4
+        self.assertEqual(actual, expected)
+
+    def test_one_way_to_make_zero_cents(self):
+        actual = change_possibilities(0, (1, 2))
+        expected = 1
+        self.assertEqual(actual, expected)
+
+    def test_no_ways_if_no_coins(self):
+        actual = change_possibilities(1, ())
+        expected = 0
+        self.assertEqual(actual, expected)
+
+    def test_big_coin_value(self):
+        actual = change_possibilities(5, (25, 50))
+        expected = 0
+        self.assertEqual(actual, expected)
+
+    def test_big_target_amount(self):
+        actual = change_possibilities(50, (5, 10))
+        expected = 6
+        self.assertEqual(actual, expected)
+
+    def test_change_for_one_dollar(self):
+        actual = change_possibilities(100, (1, 5, 10, 25, 50))
+        expected = 292
+        self.assertEqual(actual, expected)
+
+
+unittest.main(verbosity=2)