JuniorTheoryCommon

What does the program print?

Python

def countdown(n):
    if n == 0:
        return "go"
    return str(n) + countdown(n - 1)


print(countdown(3))

321go

Expecting 123go, as if the deepest call's digit came first: each call puts its own str(n) in front of the result of the next call, so 3 leads.
Expecting 3210go: at n == 0 the base case returns "go" at once, and the line that adds str(n) never runs, so 0 is not added.

JuniorTheoryCommon

Python

def countdown(n):
    if n == 0:
        return "go"
    return str(n) + countdown(n - 1)


print(countdown(3))

321go

Expecting 123go, as if the deepest call's digit came first: each call puts its own str(n) in front of the result of the next call, so 3 leads.
Expecting 3210go: at n == 0 the base case returns "go" at once, and the line that adds str(n) never runs, so 0 is not added.