HackerRank Python - Default Arguments


In this challenge, the task is to debug the existing code to successfully execute all provided test files.

Python supports a useful concept of default argument values. For each keyword argument of a function, we can assign a default value which is going to be used as the value of said argument if the function is called without it. For example, consider the following increment function:



  1. class EvenStream(object):

  2.     def __init__(self):

  3.         self.current = 0

  4. 

  5.     def get_next(self):

  6.         to_return = self.current

  7.         self.current += 2

  8.         return to_return

  9. 

  10. class OddStream(object):

  11.     def __init__(self):

  12.         self.current = 1

  13. 

  14.     def get_next(self):

  15.         to_return = self.current

  16.         self.current += 2

  17.         return to_return

  18. 

  19. def print_from_stream(n, stream=None):

  20.     stream = OddStream() if stream else EvenStream()

  21.     for _ in range(n):

  22.         print(stream.get_next())

  23. 

  24. 

  25. queries = int(input())

  26. for _ in range(queries):

  27.     stream_name, n = input().split()

  28.     n = int(n)

  29.     if stream_name == "even":

  30.         print_from_stream(n)

  31.     else:

  32.         print_from_stream(n, OddStream())
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