Expressiveness Benchmark

def unique_beer_drinkers(likes):
  likes_per_person = defaultdict(set)
  for row in likes:
    likes_per_person[row['name']].add(row['beer'])
    
  unique = []
  for p1, p1_likes in likes_per_person.items():
    is_unique = True
    for p2, p2_likes in likes_per_person.items():
      if p1 == p2:
        continue
        
      if p1_likes == p2_likes:
        is_unique = False
        break
    if is_unique:
      unique.append(p1)
      
  return unique

def unique_beer_drinkers(likes):
  people = set([row['name'] for row in likes])
  likes_per_person = {
    name: set([row['beer'] for row in likes if row['name'] == name])
    for name in people
  }
    
  return [
    name
    for name, beers in likes_per_person.items()
    if not any([
      other_name != name and beers == other_beers
      for other_name, other_beers in likes_per_person.items()
    ])
  ]

def unique_beer_drinkers(likes):
  likes_per_person = (likes
    .groupby('name')
    .beer.unique().map(set)
    .reset_index())

  def check_not_exists(row):
    other_people = likes_per_person[
      likes_per_person.name != row['name']]
    return not (other_people.beer == row['beer']).any()
  
  unique_drinkers = likes_per_person[
    likes_per_person.apply(check_not_exists, axis=1)]
  return unique_drinkers.name.tolist()

unique_beer_drinkers <- function(likes) {
  likes %>%
    group_by(name) %>%
    summarize(beer_set = list(sort(unique(beer)))) %>%
    add_count(beer_set, name = 'num_people_likes') %>%
    filter(num_people_likes == 1) %>%
    pull(name)
}

SELECT DISTINCT L1.name
FROM likes L1
WHERE NOT EXISTS(
    SELECT *
    FROM likes L2
    WHERE L1.name != L2.name
    AND NOT EXISTS(
        SELECT *
        FROM likes L3
        WHERE L3.name = L2.name
        AND NOT EXISTS(
            SELECT *
            FROM likes L4
            WHERE L4.name = L1.name
            AND L4.beer = L3.beer))
    AND NOT EXISTS(
        SELECT *
        FROM likes L5
        WHERE L5.name = L1.name
        AND NOT EXISTS(
            SELECT *
            FROM likes L6
            WHERE L6.name = L2.name
            AND L6.beer= L5.beer)))

.decl differ(a:symbol, b:symbol)
differ(A, B) :- likes(Beer, A), likes(_, B), !likes(Beer, B).
differ(A, B) :- likes(_, A), likes(Beer, B), !likes(Beer, A).

.decl exists_same(a:symbol)
exists_same(Name) :- 
  likes(_, Other), 
  likes(_, Name), 
  Name != Other, 
  !differ(Name, Other).

unique_beer_drinkers(Name) :- 
  likes(_, Name), 
  !exists_same(Name).

likes_per_person: `name xgroup likes;
counts: count each group likes_per_person;
unique_beer_drinkers: 
  (select name from likes_per_person where beer in\: where[counts=1])
  `name