1 files changed, 36 insertions, 0 deletions
diff --git a/challenge-125/roger-bell-west/python/ch-2.py b/challenge-125/roger-bell-west/python/ch-2.py
new file mode 100755
index 0000000000..b03a09c4e0
--- /dev/null
+++ b/challenge-125/roger-bell-west/python/ch-2.py
@@ -0,0 +1,36 @@
+#! /usr/bin/python3
+
+import unittest
+
+from math import degrees,atan2
+
+def btd(tree):
+  st=len(tree)
+  depth=[0]*st
+  diameter=[0]*st
+  for i in range(st-1,-1,-1):
+    if tree[i] != 0:
+      a=i*2+1
+      b=a+1
+      if b < st:
+        depth[i]=1+max(depth[a],depth[b])
+        diameter[i]=max(
+          1+depth[a]+depth[b],
+          diameter[a],
+          diameter[b]
+          )
+      else:
+        depth[i]=1
+        diameter[i]=1
+  return diameter[0]
+
+class TestBtd(unittest.TestCase):
+
+        def test_ex1(self):
+          self.assertEqual(btd([1,
+                                2,5,
+                                3,4,6,7,
+                                0,0,0,0,0,0,8,10,
+                                0,0,0,0,0,0,0,0,0,0,0,0,9,0,0,0]),7,'example 1')
+          
+unittest.main()