done 1 mobius

src/mobius.erl

@@ -10,7 +10,7 @@
 -author("ivan-igorevich").
 
 %% API
--export([is_prime/1, prime_factors/1, say/0]).
+-export([is_prime/1, prime_factors/1, is_square_multiple/1, find_square_multiples/2, say/1, start_time_check/0]).
 
 %% region is_prime
 is_prime(N) when N < 2 ->
@@ -27,9 +27,9 @@ is_prime(N, I, Max) ->
     true ->
       is_prime(N, I + 1, Max)
   end.
-%% endregion
+%% endregion is_prime
 
-%region factor
+%% region prime_factors
 prime_factors(N) ->
   prime_factors(N, 2, []).
 
@@ -42,7 +42,53 @@ prime_factors(X, N, Primes) ->
     false ->
       [X | Primes]
   end.
-%endregion
+%% endregion prime_factors
 
-say() -> io:format("The result is: ~p~n", [prime_factors(111)]).
+%% region is_square_multiple
+is_square_multiple(N)->
+  is_square_multiple_fun(prime_factors(N)).
+
+is_square_multiple_fun([H | T]) ->
+  case lists:member(H, T) of
+    true -> true;
+    false -> is_square_multiple_fun(T)
+  end;
+
+is_square_multiple_fun([]) ->
+  false.
+%% endregion is_square_multiple
+
+%% region find_square_multiples
+find_square_multiples(Count, MaxN) ->
+  find_square_multiples_fun(Count, MaxN, []).
+
+find_square_multiples_fun(Count, CurrentNumber, FoundSquareMultipleNumber)
+  when length(FoundSquareMultipleNumber) == Count  ->
+  CurrentNumber + 1;
+
+find_square_multiples_fun(_, 2, _) ->
+  fail;
+
+find_square_multiples_fun(Count, TestNumber, FoundSquareMultipleNumber) ->
+  case is_square_multiple(TestNumber) of
+    true -> FoundsNumber = FoundSquareMultipleNumber ++ [TestNumber];
+    false -> FoundsNumber = []
+  end,
+  find_square_multiples_fun(Count, TestNumber - 1, FoundsNumber).
+%% endregion find_square_multiples
+
+for(0, _, _) -> [];
+for(N, Term, Step) when N > Term ->
+  exec_time(N),
+  [Term | for(N - Step, Term, Step)].
+
+start_time_check() ->
+  for(6, 4, 1).
+
+exec_time(Depth) ->
+  Start = os:timestamp(),
+  say(Depth),
+  io:format("Depth = ~p, Time ~f sec~n", [Depth, (timer:now_diff(os:timestamp(), Start) / 1000)]).
+
+say(Depth) -> io:format("The result is: ~p~n", [find_square_multiples(Depth, 30000)]).
 

test/mobius_test.erl

@@ -10,7 +10,8 @@
 -include_lib("eunit/include/eunit.hrl").
 
 mobius_test_() -> [
-  {"Test is_prime", fun test_is_prime/0}
+  {"Test is_prime", fun test_is_prime/0},
+  {"Test prime_factors", fun test_find_square_multiples/0}
 ].
 
 test_is_prime() ->
@@ -22,3 +23,8 @@ test_is_prime() ->
   ?assertNot(mobius:is_prime(60)),
   ?assertNot(mobius:is_prime(112)),
   ?assert(mobius:is_prime(113)).
+
+
+test_find_square_multiples() ->
+  ?assertEqual(fail, mobius:find_square_multiples(3, 20)),
+  ?assertEqual(48, mobius:find_square_multiples(3, 50)).