1 files changed, 49 insertions, 0 deletions
diff --git a/challenge-236/roger-bell-west/python/ch-1.py b/challenge-236/roger-bell-west/python/ch-1.py
new file mode 100755
index 0000000000..638c1ca054
--- /dev/null
+++ b/challenge-236/roger-bell-west/python/ch-1.py
@@ -0,0 +1,49 @@
+#! /usr/bin/python3
+
+class Reserve(object):
+  def __init__(self, _vv):
+    _vq = _vv
+    _vq.sort()
+    _vq.reverse()
+    _vm = dict()
+    for i, v in enumerate(_vq):
+      _vm[v] = i
+    self.values = _vq
+    self.counts = [0] * len(_vv)
+    self.vm = _vm
+
+  def makechange(self, price, tendered):
+    val = 0
+    for bill in tendered:
+      if bill not in self.vm:
+        return False
+      self.counts[self.vm.get(bill)] += 1
+      val += bill
+    val -= price
+    for bid in range(len(self.values)):
+      while val >= self.values[bid] and self.counts[bid] > 0:
+        val -= self.values[bid]
+        self.counts[bid] -= 1
+    return (val == 0)
+
+def exactchange(a):
+  reserve = Reserve([5, 10, 20])
+  for tendered in a:
+    if not reserve.makechange(5, [tendered]):
+      return False
+  return True
+
+import unittest
+
+class TestExactchange(unittest.TestCase):
+
+  def test_ex1(self):
+    self.assertEqual(exactchange([5, 5, 5, 10, 20]), True, 'example 1')
+
+  def test_ex2(self):
+    self.assertEqual(exactchange([5, 5, 10, 10, 20]), False, 'example 2')
+
+  def test_ex3(self):
+    self.assertEqual(exactchange([5, 5, 5, 20]), True, 'example 3')
+
+unittest.main()