#!/usr/bin/perl -w
use strict;
use Time::HiRes qw/gettimeofday tv_interval/;

my(@data, %seen);
$data[$_] = int rand 100 for 0 .. 1e6 - 1;  # 1,000,000 pieces of data

my $t0 = [gettimeofday];

for (@data){
    1 unless $seen{$_}++;   # Perform a no-op the first time we see a given number
}
print "Elapsed time: ", tv_interval($t0, [gettimeofday]), " seconds\n";