http://www.perlmonks.org?node_id=935871


in reply to Re^2: Date Array Convolution
in thread Date Array Convolution

OK, here is the new code I wrote on the underground on my way to work :-) I used OO this time. The second case is your second example input, if your expected output is different, can you show it?
Update: I read the discussion you had with BrowserUk and tried to accommodate the code appropriately.
Update2: zero-intervals removed from output.
#!/usr/bin/perl use Data::Dump qw/dump/; use warnings; use strict; my $d = My::ConvoluteDate->new; while (<>) { my ($from, $to, $value) = split; $d->populate([$from, $to, $value]); } print dump $d->combine; package My::ConvoluteDate; use Data::Dump qw/dump/; use List::Util qw/min/; sub new { my $class = shift; my $self = {}; bless $self, $class; } # new sub populate { my $self = shift; while (my $triple = shift) { my ($start, $end, $value) = @$triple; push @{ $self->{times}{$start}{push} }, $value; push @{ $self->{times}{$end}{pop} }, $value; } } # populate sub combine { my $self = shift; my @result; my @stack; for my $time_string (sort keys %{ $self->{times} }) { my $time = $self->{times}{$time_string}; my $old_value = min @stack; for my $push (@{ $time->{push} }) { push @stack, $push; } for my $pop (@{ $time->{pop} }) { my $value = $pop; @stack = grep { not defined $value or $_ != $value or undef $value } @stack; } my $new_value = min @stack; if (not defined $old_value) { push @result, [$time_string]; } elsif (not defined $new_value) { push @{ $result[-1] }, $time_string, $old_value; } elsif ($new_value != $old_value) { my $end_string = $time_string; my $start_string = $time_string; if ($new_value < $old_value) { $end_string = _dec($end_string); } else { $start_string = _inc($start_string); } # avoid zero length intervals if ($result[-1][0] le $end_string) { push @{ $result[-1] }, $end_string, $old_value; } else { pop @result; } push @result, [$start_string]; } } return _day_split(@result); } # combine sub _day_split { return map { my ($start, $end, $value) = @$_; my $from = 0 + substr $start, 0, 2; my $to = 0 + substr $end, 0, 2; if ($from < $to) { my $split; my $newfrom = sprintf('%02d', $from) . '2359'; $split = [[$start, $newfrom, $value]]; push @$split, map { [sprintf('%02d', $_) . '0000', sprintf('%02d', $_) . '2359', $value] } $from + 1 .. $to - 1; my $newto = sprintf('%02d', $to) . '0000'; push @$split, [$newto, $end, $value]; @$split; } elsif ($from == $to) { $_; } else { die "Start later then end\n"; } } @_; } # _day_split sub _dec { my $time = shift; my ($day, $hour, $min) = $time =~ /(..)(..)(..)/; $min--; if ($min < 0) { $min = 59; $hour--; if ($hour < 0) { $hour = 23; $day--; die "Cannot go before 010000\n" if $day < 1; } } return sprintf '%02d' x 3, $day, $hour, $min; } # _dec sub _inc { my $time = shift; my ($day, $hour, $min) = $time =~ /(..)(..)(..)/; $min++; if ($min > 59) { $min = 00; $hour++; if ($hour > 23) { $hour = 00; $day++; } } return sprintf '%02d' x 3, $day, $hour, $min; } # _inc