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

comment on

( [id://3333]=superdoc: print w/replies, xml ) Need Help??
Your method of getting the next digit is expensive! Replace
for my $digit (@digits) { next if $digit ~~ @number; push @number, $digit; append_digit(); pop @number; }
with
for my $pos (0..$#digits) { push @number, $digits[$pos]; local @digits = @digits[0..$pos-1, $pos+1..$#digits]; append_digit(); pop @number; }

to cut down the time taken to 2/3 (6s from 9s).

Also, there's reason to use a hash (outside of testing).

Full code:

#!perl use strict; use warnings; use 5.010; our @digits = 1..9; my @number; my @results; sub append_digit { my $number = join "", @number; push @results, $number if @number && !grep $number % $_, @number; for my $pos (0..$#digits) { push @number, $digits[$pos]; local @digits = @digits[0..$pos-1, $pos+1..$#digits]; append_digit(); pop @number; } } my $stime = time; append_digit(); my $etime = time; say $etime-$stime; say "count: " . (0+@results); #say for sort { $a <=> $b } @results;

In reply to Re^2: Puzzle Time by ikegami
in thread Puzzle Time by Anonymous Monk

Title:
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?
Username:
Password:

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

How do I use this?Last hourOther CB clients
Other Users?
Others romping around the Monastery: (3)
As of 2024-04-24 07:09 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    No recent polls found