That is polynomial time (specifically quadratic).

See this stack overflow on polynomial vs. exponential: https://stackoverflow.com/questions/4317414/polynomial-time-...

Two for loops, one nested under the other, both upto N is clearly O(N^2) in the worst case. Three for loops (in the same manner) is O(N^3).

Actually, that should be:

  whoops(n):
    for i in n:
      whoops(n-1)

Your version is merely quadratic.

I don't quite understand your code, but if I'm guessing correctly that n is an integer and "for i in n" means in human terms "for all non-negative integers less than n",

that is not exponential, that is actually factorial, which is superexponential. Uh, or close to factorial, I'm not sure exactly. Testing it in python right now, incrementing a counter each time whoops is called, I'm seeing a relationship that looks like whoops(n) == n * whoops(n-1) + 1 That is interesting.

> that is not exponential, that is actually factorial, which is superexponential

Fair point; I should have given:

  whoops(n):
    if(!n) return
    for i in 2: whoops(n-1)

I think it's clear that it is "trivial to go exponential", though. And for that matter, also trivial to go superexponential apparently.

That's n^2.