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Computer Science Level 3

In his dream, Chris coded a recursive function in Python :

def rec(n):
    if n <= 0:
        return 0

    return 3 + rec(rec(n - _))

Which of the following, when substitute to _ in the $5^{\text{th}}$ line will lead to an infinite loop for some integer parameter $n$ ?

4 3 2

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Num Ic
Nov 8, 2020

the return value is 3 + something. so i checked what happened if n=3.
_ = 4 will result in return 0 -> no problem
_ = 3 will result in return 0 -> no problem
_ = 2 will again result in return 3+something -> might cause a problem

but big values for n will cause a problem for 3 and 4 too.

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