Top rank per group

# title: Top rank per group
# source: https://rosettacode.org/wiki/Top_rank_per_group
# category: Rosetta Code
# difficulty: Intro
# summary: Pick the highest-scoring row from each group with a stable tie-break on name.
# tags: popular, arrays, ranking, hashes
# vibe: 0.2

def rows
  [
    { group: "blue", name: "Ava", score: 92 },
    { group: "blue", name: "Ben", score: 88 },
    { group: "green", name: "Noah", score: 77 },
    { group: "green", name: "Mia", score: 91 },
    { group: "red", name: "Zoe", score: 84 },
    { group: "red", name: "Eli", score: 84 }
  ]
end

def better_rank?(candidate, current)
  if current == nil
    true
  elsif candidate[:score] > current[:score]
    true
  elsif candidate[:score] < current[:score]
    false
  else
    candidate[:name] < current[:name]
  end
end

def top_rank_per_group(rows)
  best = {}
  index = 0

  while index < rows.length
    row = rows[index]
    key = row[:group]
    if better_rank?(row, best[key])
      best[key] = row
    end
    index = index + 1
  end

  groups = ["blue", "green", "red"]
  output = []
  index = 0
  while index < groups.length
    output = output.push(best[groups[index]])
    index = index + 1
  end

  output
end

def run
  top_rank_per_group(rows)
end