module Day1 where
    -- All even by list comprehension and guard are in all_even.hs

    my_reverse :: [a] -> [a]
    my_reverse [] = []
    my_reverse (h:t) = reverse t ++ [h]

    colour_combo :: [String] -> [(String, String)]
    colour_combo colours = [(colour_1, colour_2) | colour_1 <- colours, colour_2 <- colours, colour_1 < colour_2]

    timestables :: [(Integer, Integer, Integer)]
    timestables = [(x, y, x * y) | x <- [1..12], y <- [1..12]]

    -- Map colouring problem - we don't want adjacent places to be the same colour
    colours = ["red", "green", "blue"]
    map_colouring :: [(String, String, String, String, String)]
    -- This just brute-forces all tuples and applies the rules, BUT it works and it uses Haskell list comprehension
    -- Although, maybe it won't brute-force ALL of them, because if al == mi then it might skip the rest
    map_colouring = [(al, mi, ga, tn, fl) | al <- colours, mi <- colours, ga <- colours, tn <- colours, fl <- colours,
                                            mi /= tn, mi /= al, al /= tn, al /= mi, al /= ga, al /= fl, ga /= fl, ga /= tn]