Language: Haskell

Source code:

import System.IO -- https://en.wikibooks.org/wiki/Haskell/Pattern_matching -- next line after commentary tells that -- function takes list of elements any type which implement a following functions: -- (+), (*), abs, signum, fromInteger, (negate | (-)) -- and return list of same type -- ++ is a list concatenation [1]++[2] == [1,2] calculate1 :: Num a =>[a] -> [a] calculate1 (x:[]) = [x*4] calculate1 (x:y:[]) = [(x+y)*5] ++ (calculate1 [y]) calculate1 (x:y:xs) = (calculate1 [x,y]) ++ (calculate1 xs) -- this function convert string(list of Char) into list of Int to_int :: [Char] -> [Int] to_int (first_element:[]) = [fromEnum first_element] to_int (first:tail) = [fromEnum first] ++ (to_int tail) -- function takes two lists and return True if they are equal compare_lists :: Eq a => [a] -> [a] -> Bool compare_lists [] (one_elem) = False compare_lists (one_elem) [] = False compare_lists (first_list1:[]) (first_list2:[]) = (==) first_list1 first_list2 compare_lists (first_list1:tail_list1) (first_list2:tail_list2) = ((==) first_list1 first_list2) && (compare_lists tail_list1 tail_list2) main = do user_input <- getLine putStrLn( show(compare_lists (calculate1 (to_int user_input)) [730,304,680,284,860,196,505,204,1020,408,1000,396,995,408,995,392,975,392,1130,500] ) )

When you run it, it waits for a string. Flag is the string for which "True" is printed.

Compiled Linux binary: main_haskell
Compiled Windows binary: main_haskell.exe