1 import unittest
   2 
   3 def countCarry(a,b, carry=0):
   4     if a+b==0:
   5         return 0
   6     carry = (a%10+b%10+carry) / 10
   7     return carry + countCarry(a/10, b/10, carry)
   8 
   9 def countCarryWithTp(a,b, tcarry=0, pcarry=0):
  10     if a+b==0:
  11         return tcarry
  12     pcarry = (a%10+b%10+pcarry) / 10
  13     tcarry += pcarry
  14     return countCarryWithTp(a/10, b/10, tcarry, pcarry)
  15 
  16 class SomeTest(unittest.TestCase):
  17     def testCountCarry(self):
  18         self.assertEquals(3, countCarry(1,999))
  19         self.assertEquals(1, countCarry(1,889))
  20         self.assertEquals(2, countCarry(555,345))
  21     def testCountCarry(self):
  22         self.assertEquals(3, countCarryWithTp(1,999))
  23         self.assertEquals(1, countCarryWithTp(1,889))
  24         self.assertEquals(2, countCarryWithTp(555,345))
  25 
  26 if __name__=='__main__':
  27     unittest.main()