#!/usr/bin/perl
use warnings;
use strict;

my @range=();
while (<DATA>){
  chomp;
  if (/^R:(.*)/){
    my ($i,undef,$s,undef,$e) = split /[, ]/,$1;
    $s = sec($s);
    $e = sec($e);
    for ($s..$e){
      $range[$_] = $i;
    }
  } else {
    my (undef,$t) = split /-/,$_;
    my $rangeid = $range[ sec($t) ];
    if ( defined $rangeid) {
      print "Found range: $rangeid for $t\n";      
    } else {
      print "No range found for $t\n";
    }
  }
}

sub sec {
  my ($h,$m,$s) = split /:/,shift;
  return $h*60*60 + $m*60 + $s
}

__DATA__
R:1,2018-03-06 14:20:00,2018-03-06 14:30:00
R:2,2018-03-06 13:00:00,2018-03-06 13:40:00
R:3,2018-03-06 13:45:00,2018-03-06 13:50:00
D:03/06/2018-14:29:41
D:03/06/2018-13:33:38
D:03/06/2018-13:54:47
D:03/06/2018-12:53:34
D:03/06/2018-13:29:19
D:03/06/2018-12:52:47
D:03/06/2018-14:21:51
D:03/06/2018-13:49:20
D:03/06/2018-13:36:18
D:03/06/2018-13:44:25