# We have four scores, two of them share the second place. This means the last
# one has to be pushed to the fourth place.

scores = [10, 9, 9, 8]

ranking, last_score, add = 0, 0, 1

rankings = scores.map do |score|
  scores.index(score) + 1
end

puts scores.inspect   # => [10, 9, 9, 8]
puts rankings.inspect # => [1, 2, 2, 4]