Fibonacci

-module(tut).
-export([fib/1]).
-export([fib2/2]).

%% Dåliga
fib ( 0 ) ->
    0;
fib ( 1 ) ->
    1;
fib ( N ) ->
    fib( N - 1 ) + fib( N - 2 ).


%% Med dynamisk programmering

fib2 ( 0, Memo ) ->
    [0];
fib2 ( 1, Memo ) ->
    [0, 1];
fib2 ( N, Memo ) ->
    case length(Memo) =< 2 of
        true -> lists:nth(N, Memo)
    end,

    case length(Memo) < N - 2 of
        false -> fib2 ( N - 2, Memo)
    end,

    case length(Memo) < N - 1 of
        false -> fib2 ( N - 1, Memo)
    end,

    lists:append([Memo, [lists:nth(N - 1, Memo) + lists:nth(N - 2, Memo)]].