public

abeaumont / majority.dylan

Created 2011-12-17

module: majority
 
define function winner (votes :: <collection>)
  let winner
    = reduce1(method (a, b) if (a.last > b.last) a else b end end,
              map(method (candidate)
                    pair(candidate, size(choose(curry(\=, candidate), votes)));
                  end,
                  remove-duplicates(votes)));
  unless (zero?(round/(winner.tail, votes.size)))
    winner.head;
  end unless;
end function winner;
 
define function print-winner (votes :: <collection>)
  let winner = winner(votes);
  if (winner)
    format-out("The winner is: %s\n", winner);
  else
    format-out("There's no winner\n");
  end;
end function print-winner;
 
define function main()
  print-winner(#['a', 'b', 'a', 'b', 'a']);
  print-winner(#['a', 'a', 'a', 'c', 'c', 'b', 'b', 'c', 'c', 'c', 'b', 'c', 'c']);
  print-winner(#['a', 'b', 'c', 'a', 'b', 'a']);
  exit-application(0);
end function main;
 
main();