k番目に大きい数（Rubyの場合）

flag = 0
k,n = 0, 0
number = Array.new

File.open("../data_d.txt","r"){|f|
  f.each{|line|
    if flag == 0
      n,k = line.split.collect{|i| i.to_i}
      flag = 1
    elsif flag && number.size < n
      number << line.to_i
    end
  }
}
p number.sort_by{|i| -i}[k-1]