feat(day-4): solution for day4 done

Author: NishantJoshi00

day-4/Makefile

@@ -2,7 +2,15 @@
 solution.beam: solution.erl
 	erl -compile solution.erl
 
+solution2.beam: solution2.erl
+	erl -compile solution2.erl
+
 build: solution.beam
+build2: solution2.beam
 
 run: solution.beam
 	erl -noshell -s solution main -s init stop
+
+
+run2: solution2.beam
+	erl -noshell -s solution2 main -s init stop

day-4/solution2.erl

@@ -0,0 +1,49 @@
+-module(solution2).
+-export([main/0]).
+
+main() -> start([]).
+
+start(Total) ->
+    case io:get_line("") of
+        eof ->
+            io:format("~p~n", [complete(lists:map(fun(X) -> [1, X] end, Total), 0)]);
+            
+        Input ->
+            [Cnt, _] = solve(string:trim(Input)),
+            start(Total ++ [Cnt])
+    end.
+
+solve(Input) -> 
+  [_, Right] = lists:map(fun string:trim/1, string:split(Input, ":")),
+  [Lookup, Rest] = lists:map(fun splitNumber/1, lists:map(fun string:trim/1, string:split(Right, " | "))),
+  LookupSet = sets:from_list(Lookup),
+  Count = operate(LookupSet, Rest, 0),
+  [Count, Rest].
+
+
+splitNumber(Input) -> lists:map(fun(X) -> {Int, _} = string:to_integer(X), Int end, re:split(Input, "\s+")).
+
+
+operate(_, [], Value) -> Value;
+operate(Set, [Fst | Rst], Value) -> 
+  State = sets:is_element(Fst, Set),
+  if 
+    State -> operate(Set, Rst, Value + 1);
+    true -> operate(Set, Rst, Value)
+  end.
+
+
+complete([], Val) -> Val;
+complete([[Cnt, _]], Val) -> Val + Cnt;
+complete([[Cnt, Itr] | Rst], Val) -> 
+  Value = sumAdd(Rst, Itr, Cnt),
+  complete(Value, Val + Cnt).
+
+
+sumAdd(Array, Count, Add) ->
+  case Count of
+     0 -> Array;
+     _Else -> 
+       [[Ctr, El] | Rst] = Array,
+       [[Ctr + Add, El]] ++ sumAdd(Rst, Count - 1, Add)
+  end.