gistfile1.rb

str = "Vitor Henry Silva Joao Maria Laube"
def abrevia_nome(str, max)

  return str if str.size <= max

  tmp = str.split(" ")
  tmp1 = tmp[1..-2]
  tmp2 = tmp[1..-2].map{|a| "#{a[0].upcase}."}
  retorno = tmp1

  final = ([tmp.first] + retorno + [tmp.last]).join(" ")
  posicao = 0
  while final.size > max && posicao < tmp2.size
    retorno[posicao] = tmp2[posicao]
    final = ([tmp.first] + retorno + [tmp.last]).join(" ")
    posicao = posicao + 1
  end

  if final.size > max
    posicao = 0
    while final.size > max && posicao < tmp2.size
      retorno[posicao] = nil
      final = ([tmp.first] + retorno.compact + [tmp.last]).join(" ")
      posicao = posicao + 1
    end    
  end

  return final[0,max]
  
end

test = *(10..str.length)
test.each do |a|
  puts abrevia_nome(str, a)
end