Speeding up Ruby by rewriting C in Ruby(jpcamara.com)

  u = ARGV[0].to_i       
  r = rand(10_000)                          
  a = Array.new(10_000, 0)                 
 
  (0...10_000).each do |i|                     
    (0...100_000).each do |j|               
      a[i] += j % u                     
    end
    a[i] += r                      
  end
 
  puts a[r]

  u = ARGV[0].to_i       
  r = rand(10_000)                                         
                    
  (0...100_000).each do |j|               
    a += j % u                     
  end
  a += r                      
  
  puts a