Data commit

Task/Amicable-pairs/Erlang/amicable-pairs-1.erl

@@ -0,0 +1,35 @@
+-module(properdivs).
+-export([amicable/1,divs/1,sumdivs/1]).
+
+amicable(Limit) -> amicable(Limit,[],3,2).
+
+amicable(Limit,List,_Current,Acc) when Acc >= Limit -> List;
+amicable(Limit,List,Current,Acc) when Current =< Acc/2  ->
+    amicable(Limit,List,Acc,Acc+1);
+amicable(Limit,List,Current,Acc) ->
+    CS = sumdivs(Current),
+    AS = sumdivs(Acc),
+    if
+        CS == Acc andalso AS == Current andalso Acc =/= Current ->
+          io:format("A: ~w, B: ~w, ~nL: ~w~w~n",  [Current,Acc,divs(Current),divs(Acc)]),
+          NL = List ++ [{Current,Acc}],
+          amicable(Limit,NL,Acc+1,Acc+1);
+        true ->
+          amicable(Limit,List,Current-1,Acc) end.
+
+divs(0) -> [];
+divs(1) -> [];
+divs(N) -> lists:sort(divisors(1,N)).
+
+divisors(1,N) ->
+     [1] ++ divisors(2,N,math:sqrt(N)).
+
+divisors(K,_N,Q) when K > Q -> [];
+divisors(K,N,_Q) when N rem K =/= 0 ->
+    [] ++ divisors(K+1,N,math:sqrt(N));
+divisors(K,N,_Q) when K * K  == N ->
+    [K] ++ divisors(K+1,N,math:sqrt(N));
+divisors(K,N,_Q) ->
+    [K, N div K] ++ divisors(K+1,N,math:sqrt(N)).
+
+sumdivs(N) -> lists:sum(divs(N)).

Task/Amicable-pairs/Erlang/amicable-pairs-2.erl

@@ -0,0 +1,7 @@
+friendly(Limit) ->
+    List = [{X,properdivs:sumdivs(X)} || X <- lists:seq(3,Limit)],
+    Final = [ X ||
+        X <- lists:seq(3,Limit),
+        X == properdivs:sumdivs(proplists:get_value(X,List))
+        andalso X =/= proplists:get_value(X,List)],
+    io:format("L: ~w~n", [Final]).

Task/Amicable-pairs/Erlang/amicable-pairs-3.erl

@@ -0,0 +1,19 @@
+friendly(Limit) ->
+    List = [{X,properdivs:sumdivs(X)} || X <- lists:seq(3,Limit)],
+    Final = [ X || X <- lists:seq(3,Limit), X == properdivs:sumdivs(proplists:get_value(X,List))
+            andalso X =/= proplists:get_value(X,List)],
+    findfriendlies(Final,[]).
+
+
+findfriendlies(List,Acc) when length(List) =< 0 -> Acc;
+findfriendlies(List,Acc) ->
+    A = lists:nth(1,List),
+    AS = sumdivs(A),
+    B = lists:nth(2,List),
+    BS = sumdivs(B),
+    if
+        AS == B andalso BS == A ->
+          {_,BL} = lists:split(2,List),
+          findfriendlies(BL,Acc++[{A,B}]);
+        true -> false
+    end.