Practice>Python>Debugging>Default Arguments

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Default Arguments

Problem link : https://www.hackerrank.com/challenges/default-arguments/problem

Difficulty : Medium

Tip

• Very interesting problem regarding default argument
• I surprised that the instance of default argument, is alive always
• Not to use same instance, we should init the instance every time
• Probably, not easy to understand, please see the solution

Solution

class EvenStream(object): def __init__(self): self.current = 0 def get_next(self): to_return = self.current self.current += 2 return to_return class OddStream(object): def __init__(self): self.current = 1 def get_next(self): to_return = self.current self.current += 2 return to_return def print_from_stream(n, stream=EvenStream()): stream.__init__() for _ in range(n): print(stream.get_next()) queries = int(input()) for _ in range(queries): stream_name, n = input().split() n = int(n) if stream_name == "even": print_from_stream(n) else: print_from_stream(n, OddStream())