#!/usr/bin/perl

# http://perlmonks.org/?node_id=1194483

use strict;
use warnings;
use Algorithm::Diff qw(traverse_sequences);

my @from = split //, shift // 'shanghai rulez';
my @to = split //, shift // 'sakhalin rulez';

my $string = '';

traverse_sequences( \@from, \@to,
  {
  MATCH     => sub { $string .= 0 },
  DISCARD_A => sub { $string .= 1 },
  DISCARD_B => sub { $string .= 2 },
  } );

printf "p=%d\tq=%d\tl=%d\n", $` =~ tr/01//, $` =~ tr/02//, length $&
  while $string =~ /0+/g;