Beefy Boxes and Bandwidth Generously Provided by pair Networks
laziness, impatience, and hubris

comment on

( [id://3333]=superdoc: print w/replies, xml ) Need Help??

Unless the individual values get very large, I think the easiest would be to factor them:

sub combine_factors { my $list = shift; my $factors = {}; for (@$list) { for (factors($_)) { ++$factors->{$_}; } } $factors; } my $fa = combine_factors(\@a); my $fb = combine_factors(\@b); ($fa->{$_} ||= 0) -= $fb->{$_} for keys %$fb; my @c = map +($_) x $fa->{$_}, grep $fa->{$_} > 0, keys %$fa; my @d = map +($_) x -$fa->{$_}, grep $fa->{$_} < 0, keys %$fa;

This has the disadvantage that it will leave a list of primes: @c == (3, 5, 11), @d == (2, 2, 2, 23). I'm not sure how you'd retain the original composites (or parts thereof), nor how you'd define which composites to keep, so I chose to ignore that aspect of it.


In reply to Re: Algorithm for cancelling common factors between two lists of multiplicands by hv
in thread Algorithm for cancelling common factors between two lists of multiplicands by BrowserUk

Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":

  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or How to display code and escape characters are good places to start.
Log In?

What's my password?
Create A New User
Domain Nodelet?
and the web crawler heard nothing...

How do I use this?Last hourOther CB clients
Other Users?
Others making s'mores by the fire in the courtyard of the Monastery: (5)
As of 2024-04-22 16:46 GMT
Find Nodes?
    Voting Booth?

    No recent polls found