#! /usr/bin/perl

use strict;
use warnings;
use Data::Dumper;

my @dates = ();
while(my $line = <DATA>) {
    my @parts = split(/&&/,$line);

    push @dates, {
        Start => $parts[0],
        End => $parts[1],
        Text  => $parts[2],
    };
}

my @colitions = ();
for(my $i = 0; $i < @dates; ++$i) {
    for(my $j = $i+1; $j < @dates; ++$j) {
        if($dates[$i]->{Start} >= $dates[$j]->{Start} && $dates[$i]->{End} <= $dates[$j]->{End} ||
           $dates[$j]->{Start} >= $dates[$i]->{Start} && $dates[$j]->{End} <= $dates[$i]->{End})
        {
            push @colitions, [{%{$dates[$i]}}, {%{$dates[$j]}}];
        }
    }
}

print "Anzahl: ", scalar @colitions, "\n",
print Dumper(\@colitions);

exit(0);

_ _DATA_ _
0800&&0900&&Eintrag1
0930&&1015&&Eintrag2
1000&&1100&&Eintrag3
1045&&1145&&Eintrag4
0800&&0830&&Eintrag5
0930&&1050&&Eintrag6
1051&&1141&&Eintrag7
1045&&1145&&Eintrag8