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Re^7: list of four digit lock combinations without repeated digits

by BrowserUk (Patriarch)
on Jun 22, 2018 at 06:12 UTC ( [id://1217160]=note: print w/replies, xml ) Need Help??


in reply to Re^6: list of four digit lock combinations without repeated digits
in thread list of four digit lock combinations without repeated digits

 push @x, pack "A*", qq[@$_] while $_=$i->next;

That would probably match if not beat join, if you weren't stringifying the array twice.

Ie. Use  push @x, pack "(A*)*", @$_ while $_=$i->next;

Of course, if you want to put all the sequences as strings into an array, this is easier and probably quicker;

my @x = map join( '', @$_ ), variations_with_repetition( ["a".."z"], 4 + );; print scalar @x;; 456976

And if all you want to do is print the count, then:

[ 7:10:21.87] C:\test>perl -MAlgorithm::Combinatorics=:all -le"print s +calar( () = variations_with_repetition( ["a".."z"], $ARGV[0] ) )" 4 456976 [ 7:10:27.12] C:\test>

BTW, that is one seriously quick machine you're running. What is it? (6x faster than my (admittedly ancient) box.


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Re^8: list of four digit lock combinations without repeated digits
by usemodperl (Beadle) on Jun 22, 2018 at 23:57 UTC
    That would probably match if not beat join, if you weren't stringifying the array twice.

    Actually you did that previously and I carelessly cargo-culted it into my code.
    However upon testing it's actually very slightly faster! I don't know why:
    perl -MBenchmark=:all -MAlgorithm::Combinatorics=:all -wle' for ("1".."4") { my $t0 = Benchmark->new; my $i = variations_with_repetition(["a".."z"],$ARGV[0]); my @x; push @x, pack "(A*)*", @$_ while $_=$i->next; my $t1 = Benchmark->new; my $ts = timestr(timediff($t1,$t0)); print $ts }' 4
    1 wallclock secs ( 0.77 usr +  0.01 sys =  0.78 CPU)
    1 wallclock secs ( 0.77 usr +  0.01 sys =  0.78 CPU)
    1 wallclock secs ( 0.75 usr +  0.00 sys =  0.75 CPU)
    1 wallclock secs ( 0.75 usr +  0.01 sys =  0.76 CPU)
    
    
    
    perl -MBenchmark=:all -MAlgorithm::Combinatorics=:all -wle' for ("1".."4") { my $t0 = Benchmark->new; my $i = variations_with_repetition(["a".."z"],$ARGV[0]); my @x; push @x, pack "A*", qq[@$_] while $_=$i->next; my $t1 = Benchmark->new; my $ts = timestr(timediff($t1,$t0)); print $ts }' 4
    0 wallclock secs ( 0.74 usr +  0.01 sys =  0.75 CPU)
    1 wallclock secs ( 0.72 usr +  0.01 sys =  0.73 CPU)
    1 wallclock secs ( 0.73 usr +  0.00 sys =  0.73 CPU)
    1 wallclock secs ( 0.74 usr +  0.01 sys =  0.75 CPU)
    
    
    
    perl -MBenchmark=:all -MAlgorithm::Combinatorics=:all -wle' for ("1".."4") { my $t0 = Benchmark->new; my $i = variations_with_repetition(["a".."z"],$ARGV[0]); my @x; push @x, join "", @$_ while $_=$i->next; my $t1 = Benchmark->new; my $ts = timestr(timediff($t1,$t0)); print $ts }' 4
    1 wallclock secs ( 0.65 usr +  0.01 sys =  0.66 CPU)
    1 wallclock secs ( 0.64 usr +  0.00 sys =  0.64 CPU)
    0 wallclock secs ( 0.63 usr +  0.00 sys =  0.63 CPU)
    1 wallclock secs ( 0.64 usr +  0.01 sys =  0.65 CPU)
    
    
    
    BTW, that is one seriously quick machine you're running. What is it?
    
    MacBook Pro i7
    3.1GHz (4.1GHz Turbo Boost) 16GB RAM 1TB SSD
    Darwin 10.13.4
    
    
    STOP REINVENTING WHEELS, START BUILDING SPACE ROCKETS!CPAN 🐪

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