-module(dna_char_count).
-export([map/1,reduce/1]).

% Given a key and a Value, representing a list of characters, 
% returns a (character,1) pair for each character in Value.
map({_,Value}) -> lists:map(fun(X) -> {X,1} end, Value).

% Given a key and list of values (Values), creates a singleton list 
% that contains the sum of the values in Values.
reduce({Key,Values}) -> {Key,[lists:foldl(fun(V,Sum) -> Sum + V end, 0, Values)]}.