Not the fastest? Let's see what we can do about it.

That's tail-end recursion, so it can be optimized:

sub equal {
   return 1 if @_ < 2;
   return 0 if $_[0] ne $_[1];
   shift;
   goto(&equal);
}

[download]

And the recursive call can be eliminated completely:

sub equal {
   while (@_ >= 2) {
      return 0 if $_[0] ne $_[1];
      shift;
   }
   return 1;
}

[download]

Benchmarks:

use strict;
use warnings;

use Benchmark qw( cmpthese );

my @list = ('1')x10;

sub equal_pm {@_ < 2 || $_[0] eq $_[1] && equal_pm(@_[1..$#_])}

sub equal_i {
   return 1 if @_ < 2;
   return 0 if $_[0] ne $_[1];
   shift;
   goto(&equal_i);
}

sub equal_i2 {
   while (@_ >= 2) {
      return 0 if $_[0] ne $_[1];
      shift;
   }
   return 1;
}

cmpthese(-3, {
   equal_pm => sub { my $rv = equal_pm(@list) ?1:0; 1; },
   equal_i  => sub { my $rv = equal_i (@list) ?1:0; 1; },
   equal_i2 => sub { my $rv = equal_i2(@list) ?1:0; 1; },
});

[download]
            Rate equal_pm  equal_i equal_i2
equal_pm 17854/s       --     -51%     -74%
equal_i  36454/s     104%       --     -46%
equal_i2 67523/s     278%      85%       --

[download]

In reply to Re^2: Testing the Uniformity of an Array by its Elements by ikegami
in thread Testing the Uniformity of an Array by its Elements by neversaint

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