Beefy Boxes and Bandwidth Generously Provided by pair Networks
more useful options
 
PerlMonks  

Re^8: [OT:] Is this Curriculum right?

by LanX (Saint)
on Nov 27, 2021 at 11:38 UTC ( [id://11139170]=note: print w/replies, xml ) Need Help??


in reply to Re^7: [OT:] Is this Curriculum right?
in thread [OT:] Is this Curriculum right?

> I have not studied how Perl implements its hash tables; I hope to find more time to study them in the future.

see https://st.aticpan.org/source/RURBAN/illguts-0.49/index.html#hv

the collisions for a bucket are stored in a linked list.

> Agreed. I too find Perl's arrays a delight to use. :)

Perl arrays use a doubling trick to ensure that push and unshift are near O(1) like with linked lists.

They allocate more memory than needed, and start and end are given by pointers° inside that area. In the rare cases it's exhausted, twice as much memory is dynamically allocated and the data transferred.

So its space for time and the cost for re-allocation is reduced to a constant on average.

And splice'ing should still be far more expensive than with linked lists.

Cheers Rolf
(addicted to the Perl Programming Language :)
Wikisyntax for the Monastery

°) kind of a sliding window

Replies are listed 'Best First'.
Re^9: [OT:] Is this Curriculum right?
by ikegami (Patriarch) on Nov 28, 2021 at 01:42 UTC

    Perl arrays use a doubling trick to ensure that push and unshift are near O(1) like with linked lists.

    Unshifts are O(1).

    Unshifts and pushes are amortized O(1) (meaning O(N) to do N of them).

      > Unshifts are O(1).

      Please explain why not "amortized O(1)", the cases are symmetric.

      Cheers Rolf
      (addicted to the Perl Programming Language :)
      Wikisyntax for the Monastery

        Sorry, was thinking of shift.

Log In?
Username:
Password:

What's my password?
Create A New User
Domain Nodelet?
Node Status?
node history
Node Type: note [id://11139170]
help
Chatterbox?
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: (6)
As of 2024-04-19 16:43 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    No recent polls found