Beefy Boxes and Bandwidth Generously Provided by pair Networks
Perl Monk, Perl Meditation

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
The runtime scales with the product of the sizes of the two arrays.
So? ;-) No matter what method you choose, worst case, the runtime will be at least proportional to the product of the sizes of the two array, if only because that can be the output size. See below.
my %b_hash = map { $_ => 1 } @b_array; my @new_array = grep $b_hash{$_}, @a_array;
You (and I think all of the others who answered this question) just failed question 1b. This will only work if the elements of @b_array are unique - but that's not given, and you shouldn't make that assumption; at least not without mentioning it.

I'd do something like:

my %b_hash; $b_hash {$_} ++ for @b_array; my @c_array = map {($_) x ($b_hash {$_} || 0)} @a_array;
which has a running time of O (sizeof (input) + sizeof (output)), which is asymptotical optimal.


In reply to Re: (OT) Interview questions -- your response? by Abigail-II
in thread (OT) Interview questions -- your response? by Ovid

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

  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.
  • Log In?

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

    How do I use this? | Other CB clients
    Other Users?
    Others chanting in the Monastery: (5)
    As of 2019-07-18 21:34 GMT
    Find Nodes?
      Voting Booth?

      No recent polls found