Richard A. O'Keefe
Fri Mar 31 01:08:43 CEST 2006
Raimo Niskanen <> wrote:
Regarding your problem about determining the number of decimal
digits in a number, I just came to think of a simple enough
brute force O(log(N)) or rather O(NN) where NN is the
number of digits in the number:
digits(N) when is_integer(N), N >= 0 -> digits(N, 1, 0).
digits(N, M, D) when M > N -> D;
digits(N, M, D) -> digits(N, M*10, D+1).
I am reading "O(NN)" as "O(#Digits)".
Unfortunately, this is O(#Digits**2), because the multiplication M*10
is O(#Digits), not O(1).
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