python: add problem 67 and unittest

Author: supercoderhawk

Python/sln_1_100/solution_61_70.py

@@ -0,0 +1,32 @@
+# -*- coding: utf-8 -*-
+
+class Solution_61_70(object):
+    def addBinary(self, a, b):
+        """
+        67
+        :type a: str
+        :type b: str
+        :rtype: str
+        """
+        if len(a) > len(b):
+            max_len = len(a)
+            b = '0' * (len(a) - len(b)) + b
+        else:
+            max_len = len(b)
+            a = '0' * (len(b) - len(a)) + a
+
+        result = []
+        carry = 0
+        for ch_a, ch_b in zip(a[::-1], b[::-1]):
+            bit = int(ch_a) + int(ch_b) + carry
+            if bit > 1:
+                result.append(str(bit - 2))
+                carry = 1
+            else:
+                result.append(str(bit))
+                carry = 0
+
+        if carry == 1:
+            result.append('1')
+
+        return ''.join(result[::-1])

Python/sln_1_100/test_solution_61_70.py

@@ -0,0 +1,10 @@
+# -*- coding: utf-8 -*-
+from sln_1_100.solution_61_70 import Solution_61_70
+from unittest import TestCase
+class TestSolution_61_70(TestCase):
+    def setUp(self):
+        self.sln = Solution_61_70()
+
+    def test_addBinary(self):
+        ret = self.sln.addBinary('11','1')
+        print(ret)