uniq.rb

require 'benchmark'

ary = []
itrts = 50_000_000
code_range = 1e+13.to_i...4e+13.to_i
itrts.times do |i|
	ary << rand(code_range)
end

puts Benchmark::CAPTION
puts Benchmark.measure{
	10.times do ary.uniq end
}

#$ ruby uniq.rb 
#      user     system      total        real
#524.510000  15.080000 539.590000 (539.669947)