python: add problem 38 and test function

Author: supercoderhawk

Python/solution_31_40.py

@@ -0,0 +1,23 @@
+# -*- coding: UTF-8 -*-
+
+class Solution_31_40:
+  def countAndSay(self, n):
+    """
+    :type n: int
+    :rtype: str
+    """
+    curr = '1'
+    for i in range(1, n):
+      prev = curr
+      curr = ''
+      count = 1
+      say = prev[0]
+      for ch in prev[1:]:
+        if say == ch:
+          count += 1
+        else:
+          curr += str(count) + say
+          say = ch
+          count = 1
+      curr += str(count) + say
+    return curr

Python/test_solution_31_40.py

@@ -0,0 +1,13 @@
+from unittest import TestCase
+
+from solution_31_40 import Solution_31_40
+
+
+# -*- coding: UTF-8 -*-
+class TestSolution_31_40(TestCase):
+  def setUp(self):
+    self.sln = Solution_31_40()
+
+  def test_countAndSay(self):
+    self.assertEqual(self.sln.countAndSay(2), '11')
+    self.assertEqual(self.sln.countAndSay(4), '1211')