adventofcode/2021/day3/day3.erl

%% to compile: erlc day3A.erl
%% to run: erl -noshell -s day3 solve
%%
-module(day3).

-export ([solve/0, solve/1, solve/2]).

solve() ->
    solve(['1']),
    solve(['2']),
    init:stop().

solve(A) ->
    solve(A, get_data()).

solve(['1'], D) ->
    io:format("The solution to ~p puzzle1 is: ~p~n", [?MODULE, solve(1, D)]);
solve(1, D) ->
    solution1(D);
solve(['2'], D) ->
    io:format("The solution to ~p puzzle2 is: ~p~n", [?MODULE, solve(2, D)]);
solve(2, D) ->
    solution2(D).

solution1(D) ->
    Count_list = get_count_list(D),
    Gamma =    [ case Ones > Zeros of 'true' -> $1; 'false' -> $0 end  || {Ones, Zeros} <- Count_list],
    Epsilion = [ case Ones > Zeros of 'true' -> $0; 'false' -> $1 end  || {Ones, Zeros} <- Count_list],
    bl2int(Gamma) * bl2int(Epsilion).

solution2(D) ->
    Most_common  = fun(X,Y) -> X >= Y end,
    Least_common = fun(X, Y) -> X < Y end,
    get_rating(D, Most_common) * get_rating(D, Least_common).

get_rating(D, Fun) ->
    get_rating(D, Fun, 1).

get_rating([D], _, _) ->
    bl2int(D);
get_rating(D, Fun, Pos) ->
    Count_list = get_count_list(D),
    {Ones, Zeros} = lists:nth(Pos, Count_list),
    New_list = 
    case Fun(Ones,Zeros) of
        'true'  -> filter_list(D, Pos, $1);
        'false' -> filter_list(D, Pos, $0)
    end,
    get_rating(New_list, Fun, Pos + 1).

%%
%% Internal functions
%%
% Return a Filtered list where postion Pos is V
filter_list(L, Pos, V) ->
    lists:filter(fun(X) -> lists:nth(Pos, X) == V end, L).

%% return a list [{Ones1,Zeros1},{Ones2,Zeros2}...] when OnesX is count of 1's in column X and ZerosX is count of zeros in column X
get_count_list([H|_] = D) ->
    get_count_list(D, init_acc(length(H), [])).

get_count_list([], Acc) ->
    Acc;
get_count_list([H|T], Acc) ->
    get_count_list(T, lists:zipwith(fun(X, {Ones, Zeros}) ->
                      case X of $1 -> {Ones + 1, Zeros}; $0 -> {Ones, Zeros + 1} end
                   end, H, Acc)).

%% create a list of {0,0} tuples of length L, e.g. if L = 3 then return [{0,0},{0,0},{0,0}]
init_acc(0, Acc) ->
    Acc;
init_acc(Len, Acc) ->
    init_acc(Len - 1, Acc ++ [{0,0}]).

%% Convert binary list to integer, e.g. "1011" -> 11 dec
bl2int(CL) ->
    io:format("convert ~p~n", [CL]),
    bl2int(lists:reverse(CL), 0, 0).

bl2int([], Acc, _) ->
    Acc;
bl2int([H|T], Acc, Mult) ->
    bl2int(T, Acc + ((H - $0) * math:pow(2,Mult)), Mult + 1).    

get_test_data() ->
[
"00100",
"11110",
"10110",
"10111",
"10101",
"01111",
"00111",
"11100",
"10000",
"11001",
"00010",
"01010"
].

get_data() ->
[
"010100110111",
"101001010000",
"101011110010",
"100100011101",
"101000011000",
"110011011110",
"111010010100",
"001111100000",
"111101100001",
"100010101110",
"101101110101",
"010010101110",
"111001110100",
"000101111000",
"111101111100",
"000010001100",
"101010111101",
"001010011011",
"001101101101",
"000000110100",
"001100101011",
"110110110010",
"001110000011",
"011001111001",
"110100110011",
"011000110001",
"111100100010",
"101011000000",
"011101000111",
"011111000111",
"111011001110",
"011111010100",
"001110110001",
"010110110001",
"100111011011",
"100110100100",
"110010111000",
"101111001100",
"101111111001",
"000001000110",
"100010010110",
"110111100101",
"001001010101",
"001110001011",
"101111001011",
"111011110010",
"101001001100",
"101010100001",
"000000111101",
"100000000111",
"111010111101",
"000110110111",
"100100101111",
"110101100101",
"011010110010",
"110100001110",
"001011011010",
"010101010101",
"011110000100",
"010000000010",
"010111010111",
"011010011100",
"101101001011",
"000111100101",
"101111001000",
"000100010000",
"111000011111",
"100001010101",
"011101111110",
"001111011110",
"001100111111",
"000011000100",
"001011101010",
"001011010111",
"101001001110",
"010101011001",
"110101001011",
"011110011110",
"001000110010",
"011101110001",
"101110000000",
"000001100111",
"110111000011",
"001001111010",
"100100000000",
"000000011101",
"111110111011",
"101001111100",
"110110100010",
"101011011000",
"000111100010",
"011000110100",
"111100100100",
"010010100000",
"111101001011",
"111001000000",
"001001000001",
"010010100001",
"110110001100",
"001101100001",
"011110010110",
"100111011101",
"001001110110",
"001001100011",
"011001111010",
"110110010111",
"110100111010",
"111110011100",
"100000100111",
"010001101101",
"110100110101",
"101111101001",
"100110010000",
"100011001111",
"101111001010",
"001110111001",
"111101001101",
"001010111101",
"010010011010",
"100101101111",
"100000011110",
"011111010001",
"000010001101",
"010100101100",
"001010001100",
"100111011100",
"011110000000",
"100000011111",
"000010010100",
"000001001101",
"011111011111",
"100101001101",
"000100010110",
"011011111100",
"000111000011",
"010100101011",
"011000101111",
"001001100111",
"110111110100",
"111101111011",
"110011010101",
"100111111111",
"010100010000",
"001111110101",
"010011010001",
"101000111111",
"000001110100",
"010010010000",
"100010000101",
"110111100111",
"001011111101",
"101100101101",
"001010110100",
"000100110001",
"111101110110",
"111110101110",
"100011100110",
"011001001010",
"001000010111",
"010001110110",
"011110000010",
"101010101111",
"110100100100",
"010001100101",
"001011111110",
"100111100000",
"111101000010",
"101101011110",
"101100111100",
"001110011100",
"110110100101",
"000110111010",
"011001010111",
"010001000011",
"100010010111",
"000110110000",
"001000010101",
"010011010010",
"110000100010",
"010000101110",
"010110111000",
"011101001000",
"011110000111",
"100110100011",
"110011001001",
"001110000111",
"000001101110",
"001000100110",
"011101111000",
"101100000101",
"110001100000",
"101000100101",
"110101110101",
"111000101111",
"101000101001",
"101000100000",
"101011010110",
"000010111100",
"011101101000",
"000110101001",
"000110110110",
"100111001011",
"100010001101",
"101111000111",
"100100111000",
"100100111100",
"000000100010",
"100110000111",
"101110001100",
"110010010010",
"100110010011",
"100100000011",
"000001011111",
"110100100000",
"000000111100",
"110110010001",
"001101111110",
"010011010011",
"001000111110",
"100010010100",
"000111110101",
"111111101001",
"100110001110",
"101011011101",
"110100100010",
"010100001000",
"100111101001",
"010111010001",
"001110101000",
"100111101111",
"100010101011",
"101111100111",
"111001100110",
"111100110101",
"001101001111",
"111011011111",
"011011100110",
"101111011000",
"100110110001",
"100010011101",
"000111010101",
"101101011100",
"111010100100",
"001101000100",
"101111100101",
"010110001010",
"111101010000",
"100111110100",
"100000000011",
"010001111110",
"011010001110",
"110100010100",
"010100111100",
"011001101100",
"110101001001",
"000011100111",
"011000000000",
"110001000011",
"101011001101",
"001010110000",
"010000011010",
"101110101010",
"001010011111",
"011101000101",
"110011101010",
"101110001110",
"100111110000",
"100100010100",
"010011101000",
"100110000110",
"111100010011",
"011101101011",
"100110010100",
"011011100001",
"011111100110",
"111100101111",
"000111101001",
"100101011101",
"010101001110",
"110011110011",
"111011011100",
"101001101111",
"100001010111",
"110010111001",
"011011101011",
"111110001010",
"000010111110",
"011010000101",
"011011000111",
"110000000101",
"010110111011",
"010110110000",
"011000110110",
"100101001000",
"000111110001",
"011110000101",
"001000010000",
"011011000011",
"100101100011",
"010000100000",
"100010011000",
"001011100001",
"000110100010",
"011000111010",
"100011001011",
"101111111010",
"001100110101",
"101100111111",
"010011100111",
"001110110010",
"000100100110",
"010100010001",
"100100011011",
"110110100100",
"100011011001",
"110001000110",
"110110100000",
"101110001010",
"000100101010",
"000000100110",
"110110111110",
"011000111101",
"001101111000",
"110001100001",
"101011011100",
"101100001000",
"100000111011",
"011110010100",
"010000101111",
"100011100101",
"100111010100",
"000011010110",
"111010110011",
"010101000001",
"001101010100",
"010001010011",
"100011000101",
"011100011111",
"100101100010",
"011111011100",
"011010010000",
"011011011110",
"101000000100",
"110111111100",
"100111110011",
"110100010010",
"100100011111",
"000100001101",
"001101100010",
"000001010110",
"110110010010",
"001110000110",
"101100110101",
"111000110011",
"111110111111",
"001000111000",
"010101111010",
"010011101010",
"010010100100",
"000101001011",
"010011011010",
"100110111011",
"100011110111",
"111001001011",
"011000000111",
"000101101101",
"001000011100",
"110111111010",
"011010101001",
"110000010101",
"011001110010",
"001001001011",
"111010110110",
"101010000110",
"110111010011",
"101110011010",
"011111110101",
"010100110011",
"010000100111",
"010100001011",
"011111010110",
"110011111110",
"100100111101",
"000100111001",
"011011101111",
"111010001101",
"100000110101",
"110000000010",
"111110101011",
"011000010110",
"001011101100",
"010001110011",
"111010111010",
"100010011110",
"001100000011",
"000101110000",
"111011101111",
"111000000111",
"100101011100",
"010111000010",
"010010111010",
"001111111100",
"101001000000",
"000010111111",
"001110011000",
"111110011110",
"101101000110",
"101110100110",
"100011011100",
"101100000001",
"111001111011",
"101010101000",
"010111101110",
"000010100101",
"100010111000",
"101111000100",
"000010011101",
"011000111011",
"010110011011",
"010101100010",
"100101010111",
"011010101110",
"110011011011",
"110100101011",
"110110111100",
"000101110011",
"011001110101",
"111000100100",
"101010000001",
"110111100011",
"100001000110",
"001101011111",
"101010000101",
"011111111000",
"000111011110",
"100001111101",
"011010010010",
"101010011100",
"101110101100",
"000001010100",
"101010100110",
"001100101010",
"101110100100",
"100100111001",
"110010100111",
"000100001110",
"111001110101",
"110000101110",
"000010011000",
"010001110010",
"000100010011",
"011110100001",
"001010111010",
"010010111001",
"010001001011",
"101101001110",
"011001000110",
"110110011001",
"110111000000",
"011010111001",
"001000010001",
"010110011100",
"000111110010",
"101110000010",
"000101001100",
"110010111101",
"001101010000",
"010010011001",
"010000010111",
"011110011100",
"111000100011",
"110101011000",
"101100100010",
"111111100110",
"010011111110",
"111110000100",
"100010100100",
"101110111100",
"110000010010",
"011010000110",
"000101100101",
"001011001000",
"111000110001",
"000010001011",
"111000010000",
"100000101000",
"001101011101",
"101000101100",
"010100111010",
"101100000110",
"001111010011",
"011111110011",
"101000100010",
"111000001111",
"111000111010",
"001110000101",
"110001010011",
"011101011010",
"101001000101",
"111111001110",
"111110110101",
"110001110100",
"101101010101",
"000100011111",
"101100100110",
"000111011000",
"101010110001",
"000100110110",
"101101110111",
"100011101000",
"010011110101",
"110101111001",
"110001110011",
"000100111100",
"010011010110",
"101100000100",
"011011101000",
"101110000100",
"100100010110",
"111011100100",
"011010110000",
"100111011010",
"110100011010",
"101111111111",
"110110011100",
"110011100101",
"100001111100",
"111101100110",
"110010001010",
"010001001101",
"101110100001",
"111101001100",
"110101000100",
"011001110000",
"010110100011",
"111111000001",
"110010100000",
"101100110000",
"110000000000",
"001101110111",
"001100001000",
"001101101000",
"101100100011",
"001001011011",
"011011101110",
"010011111000",
"110100111000",
"011001101010",
"111011111010",
"100011111010",
"001011011110",
"111101100101",
"100011100100",
"101110101000",
"000111110110",
"100111010001",
"110000011100",
"111111111110",
"110100010101",
"101001110011",
"000010001110",
"000010001001",
"110000110000",
"001001000110",
"110111110000",
"010101010010",
"111101110001",
"110101101101",
"010111000111",
"111010110111",
"001011011011",
"001001100001",
"101000101110",
"101100110010",
"100100100100",
"011110111001",
"011100000110",
"100110110111",
"111010001110",
"110111111011",
"011010111000",
"011101100001",
"011110001111",
"110101011011",
"000000001111",
"101000001110",
"111010101110",
"001100001110",
"010111000101",
"111100111110",
"001110101110",
"011101111010",
"011100001111",
"000000000101",
"111111000100",
"000110010101",
"001101000010",
"111001111100",
"101100010100",
"001011001001",
"010110000010",
"010001101000",
"001111101111",
"011011011011",
"111110000001",
"100111011000",
"011000000110",
"100111101110",
"101100000000",
"101011000100",
"111000011101",
"100001101001",
"100001101000",
"011110001001",
"110110011011",
"011100010111",
"000100111000",
"000110000001",
"000111001100",
"000111111010",
"110110000001",
"000010011010",
"100000101001",
"101110001011",
"100010110101",
"110011010000",
"111101111111",
"100101011110",
"101110011111",
"111111011111",
"011010010110",
"010100101010",
"001010100001",
"000000110110",
"110000111101",
"010101101011",
"110100100001",
"011110001110",
"111001010011",
"001000001000",
"000011111110",
"111000100110",
"100100101000",
"011011000110",
"111001100011",
"111100101000",
"110001100010",
"011000000001",
"111101010010",
"001011000100",
"010100110110",
"000001111101",
"001010000011",
"010010100110",
"100000011101",
"101011010011",
"000111110000",
"101001001011",
"100000001000",
"010000111100",
"000100101011",
"011101010000",
"101101010010",
"100010011001",
"001101100101",
"101010010100",
"111011111001",
"101000010001",
"001111000000",
"011001000010",
"100101010110",
"000100001100",
"010000101000",
"110001111111",
"000101010111",
"110100101110",
"111100110001",
"101011000001",
"101100101110",
"110000101100",
"101100111110",
"111000010110",
"010110101110",
"001010100110",
"110011010010",
"111001100000",
"100100100001",
"000011011001",
"111011011110",
"011110000011",
"101000100001",
"101010010001",
"101001100001",
"100011001010",
"100000000110",
"010000100001",
"001011011001",
"110111010100",
"111001000111",
"111111110010",
"101010100101",
"100110001011",
"010110011001",
"110001111110",
"100100000111",
"110001110111",
"101110010101",
"010010111000",
"000000011001",
"101110000011",
"100001010000",
"001100001011",
"111111001100",
"111010010010",
"010011100001",
"100001111000",
"000010000110",
"010100011100",
"101111101010",
"100110010101",
"101001101001",
"100110101001",
"001001011100",
"001100011101",
"001100011001",
"000100100100",
"100011010100",
"000100001011",
"111101100011",
"011010001011",
"111000101101",
"101000010000",
"010110001111",
"111100010110",
"000111111101",
"100100111011",
"101011000010",
"011001100010",
"101111011100",
"101001110101",
"101111101100",
"110101001111",
"111101100000",
"101110011011",
"100101110000",
"001100111110",
"010010101010",
"001100100100",
"001010101100",
"001101100111",
"110010011100",
"010000001001",
"011011110001",
"100101110001",
"101111100100",
"110101101000",
"110000100000",
"101010011101",
"111000010011",
"100001010100",
"000101101010",
"101111001001",
"000110101101",
"101011010111",
"000001001100",
"100100111110",
"000010111011",
"000100000100",
"100100001110",
"011010000001",
"010101110011",
"111101101101",
"101110101111",
"100010100011",
"110001011101",
"110001011011",
"100011110011",
"111000011011",
"110101110010",
"000110010100",
"101000001010",
"011001011010",
"111000001101",
"101001101101",
"111001000001",
"000100000110",
"110000000110",
"010011001110",
"011101000001",
"010000101101",
"010011011001",
"010101001111",
"011110110001",
"100111110001",
"101111011101",
"111001000010",
"111111111000",
"001011101011",
"001010100111",
"111110111101",
"011111011101",
"000100111101",
"010010000101",
"001111101011",
"110010100100",
"110001011001",
"010111111000",
"100100101110",
"110111011101",
"100100000110",
"111111011011",
"101101111001",
"111011010001",
"000000011100",
"011011101001",
"100010111101",
"110111000110",
"001100110010",
"111100111100",
"111111000010",
"100111010111",
"100011001100",
"110101011100",
"001111001100",
"101010000010",
"110011010111",
"110011010001",
"001110110110",
"000011011100",
"001011001011",
"100000000001",
"110000100011",
"011011110011",
"100101100100",
"011100100011",
"100001110111",
"011101001001",
"011101100011",
"011001001101",
"011001000100",
"010111001111",
"100001001111",
"101001100000",
"110010001011",
"010101011100",
"011110110010",
"111010000110",
"000010100100",
"110111000111",
"001011010110",
"010001000100",
"110100010111",
"010101100110",
"010011101111",
"101000001000",
"011011001011",
"100001000001",
"101111110011",
"100110110011",
"100011100000",
"101101000010",
"000101011000",
"111101110010",
"110111010110",
"101110000110",
"110010110001",
"000001101111",
"110101101111",
"000010111010",
"100010010001",
"111010011001",
"011110011011",
"000110101010",
"010100001111",
"010111011000",
"000011110100",
"010001010101",
"110111011001",
"010001111001",
"111010111111",
"010010010001",
"010001100011",
"111110001001",
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