Sunday, January 4, 2015

December 2014 1HaskellADay Problems and Solutions

December 2014
  • December 30th, 2014: Why can't we all just consensus along? for today's Haskell problem Pro-, con-, anti-, ... it's all sensus to me!
  • December 29th, 2014: Uh, wait! What? It's another day? We need another #haskell puzzler? Here ya go! Rosalind subs (not grinders) Rose petals falling ... and a soution to the #rosalind subs problem
  • December 24th, 2014: A||B||C == Merry Christmas for today's haskell problem
  • December 23rd, 2014: Convergence, but not the movie, is today's #haskell problem A rational solution was posted by @sheshanaag at 
  • December 22rd, 2014: Yesterday was about the zeroes, today's haskell problem is about the squares
  • December 21nd, 2014: In which we want to have the most zeros. Fancy that! (I guess we're not playing Dodgeball, then!)
  • December 19th, 2014: A question for today's #haskell problem: how do YOUclear a Writer monad's log? A FlushableWriter solutionwas posted by @aditcr8 at
  • December 18th, 2014: Why can't you spell 'PROTEIN' with proteins? The solution for this problem is to Eat your proteins, young man!
  • December 17th, 2014: In which we find out that Mendel was into the Domme-scene for today's #haskell problem Whether hetero- or homo- a zygous is still a zygous... whatever that is. A solution to today's #haskell-zygous problem is posted at
  • December 16th, 2014: All actors should relate to today's #haskell problem; it's all about H-A-M-M! Go HAMM it up; #Rosalind will love you. And the solution is so HAMMy!
  • December 15th, 2014: Wanna Date? In which Jane Austen writes today's #haskell problem in her modern book titled: "The Hook Up" aka Pride and Prejudice. To get to our solution space, first we have to write an l-expr scanner/parser, of course.
  • December 12th, 2014: In this case 'GC' does NOT mean 'garbage collection' for today's #rosalind #haskell problem Yeah, not garbage-collected, but a solution, nonetheless 
  • December 11th, 2014: Why ... you ... wascally wabbit! Today's #haskell problem has a solution multiplying like Fibonaccis! I mean: rabbits. And speaking of rabid rabbits, the solution is there. BLARGH! 
  • December 10th, 2014: "Hello, Strand, you're looking lovely in that dress!" Complimenting DNA for today's #haskell problem. No, wait: 'comPLEmenting' a strand of DNA. Sorry, Miss Rosalind! A nicely complimented solution to the DNA-complement problem posted at
  • December 9th, 2014: I think this is my week with dear Rosalind: DNA-to-RNA transcriber for today's #haskell problem Another #TweetedHaskellSolution posted to for today's DNA-to-RNA transcriber
  • December 8th, 2014: Rosalind, dear Rosalie, wherefore art thou givest me bioinformatic puzzles to solve, counting nucleotides? #haskell Nucleotide-counter, HO! A nucleotide-counting solution is posted at 
  • December 5th, 2014: This visit to Liar's-berg (or is it Truth-town?) we encounter only two women, so this should be 2x as easy to solve By coercion, we find that we are in Liarsberg, after all:
  • December 4th, 2014: Gadzooks! It's (past) that time of day again for the daily #haskell problem. Here: eat some glow worms!
  • December 3rd, 2014: Substantive citizens (with some substantive hints, for a change) for today's #haskell problem
  • December 2nd, 2014: There are some curious fractions to find for today's #haskell problem at Asolution to this curious fraction problem is posted at
  • December 1st, 2014: Today's Haskell problem is all about lambda-terms. It has NOTHING to do with for-loops and if-statements, ... NOT ONE BIT Solution: 

1 comment:

Dave Turner said...

Hi Geophf,

For the one from 19th Dec about clearing a Writer's log, you can do this just by changing the underlying monoid. I don't know whether there's an official name for this construction, but I've called it 'ClearBefore' in the following: