Your problem starts here 

    my @arr_b = grep { $_ % 3600 == 0 } ($start_b .. $end_b); 
    my @arr_a = grep { $_ % 3600 == 0 } ($start_a .. $end_a);

[download]

Sure, I hate to do math too, esp the fuzzy date math, but DateTime::Span already does the math for us :) no need to generate ranges like some ruby programmer :)

With my modification I get 5 second speedup 

$ perl -s timeoverlap.961234.pl
Start: Sun Mar 25 06:53:28 2012
Start: 0
unit6;449
unit2;1014
End: Sun Mar 25 06:53:34 2012
End: 6

$ perl -s timeoverlap.961234.pl -withDateTime
Start: Sun Mar 25 06:53:37 2012
Start: 1
unit6;447
unit2;1013
End: Sun Mar 25 06:53:37 2012
End: 1

[download]

Sure my numbers don't exactly match yours but they're close enough :) maybe even more correct; here is my modification, add it to your program after split 

    use vars qw/ $withDateTime /;
    if( $withDateTime  ){
        use if $withDateTime,qw/ DateTime::Span /;
        use if $withDateTime,qw/ DateTime::Format::Strptime /;
#~         use DateTime::Span;
#~         use DateTime::Format::Strptime;
        my $strp = DateTime::Format::Strptime->new(
#~                 29.10.2008 13:00:00
#~                 %d.%m.%Y   %T
            pattern => '%d.%m.%Y %T',
        );
        
        my $span_a = DateTime::Span->from_datetimes(
            start => $strp->parse_datetime($start_a_str),
            end => $strp->parse_datetime($end_a_str),
        );
        my $span_b = DateTime::Span->from_datetimes(
            start => $strp->parse_datetime($start_b_str),
            end => $strp->parse_datetime($end_b_str),
        );
        my $set = $span_a->intersection( $span_b );
        my $dur = $set->duration;
        my $thours = 0;
        $thours += $dur ->years *365*24;
        $thours += $dur ->months *30*24;
        $thours += $dur ->weeks *7*24;
        $thours += $dur ->days *24;
        $thours += $dur ->hours ;
        $thours += $dur ->minutes  / 60 ;
        $thours += $dur ->seconds  / 60 / 60 ; # irrelevant
        $thours = sprintf '%.f', $thours; # round 
        $hash{$wds} +=  $thours if $thours;
        next STRING;
    }

[download]

And sure, DateTime::Duration is annoying and could have used some kind of  total_as_hours but it sure beats ranges :)

In reply to Re: Calculation of the time overlapping by Anonymous Monk
in thread Calculation of the time overlapping by vagabonding electron

Title:
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, details, 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, summary, 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.