1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
|
-module(ch2).
-export([mad/1]).
-spec zip(L1,L2) -> R when
L1 :: [T],
L2 :: [T],
R :: [{T,T}],
T :: integer().
zip(L1, L2) -> lists:reverse(zip(L1, L2, [])).
-spec zip(L1,L2,R) -> R when
L1 :: [T],
L2 :: [T],
R :: [{T,T}],
T :: integer().
zip([], _, Acc) -> Acc;
zip(_, [], Acc) -> Acc;
zip([X | Xs], [Y | Ys], Acc) ->
zip(Xs, Ys, [{X, Y} | Acc]).
-spec mad(L) -> R when
L :: [T],
R :: [{T,T}],
T :: integer().
mad([]) -> [];
mad([_]) -> [];
mad(L) ->
Sorted = lists:sort(L),
Pairs = zip(Sorted,tl(Sorted)),
Diffs = lists:map(fun({A,B}) -> abs(A - B) end,Pairs),
Min = lists:min(Diffs),
[{A,B} || {A,B} <- Pairs, abs(A - B) =:= Min].
|
