1 files changed, 35 insertions, 0 deletions
diff --git a/challenge-249/roger-bell-west/python/ch-2.py b/challenge-249/roger-bell-west/python/ch-2.py
new file mode 100755
index 0000000000..a242036ab7
--- /dev/null
+++ b/challenge-249/roger-bell-west/python/ch-2.py
@@ -0,0 +1,35 @@
+#! /usr/bin/python3
+
+def distringmatch(a):
+  v = 1 << (len(a) - 1)
+  wv = v << 1
+  out = [wv]
+  for c in a:
+    if c == "I":
+      wv += v
+    else:
+      wv -= v
+    v >>= 1
+    out.append(wv)
+  c = dict()
+  q = out.copy()
+  q.sort()
+  for i, v in enumerate(q):
+    c[v] = i
+  return [c[v] for v in out]
+      
+
+import unittest
+
+class TestDistringmatch(unittest.TestCase):
+
+  def test_ex1(self):
+    self.assertEqual(distringmatch("IDID"), [0, 4, 1, 3, 2], 'example 1')
+
+  def test_ex2(self):
+    self.assertEqual(distringmatch("III"), [0, 1, 2, 3], 'example 2')
+
+  def test_ex3(self):
+    self.assertEqual(distringmatch("DDI"), [3, 2, 0, 1], 'example 3')
+
+unittest.main()