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

while (<DATA>) {
    @off = split( /' '/, $_ );
    %find = ( "start" => $off[0], "stop" => $off[1] );
    my $hash_ref = \%find;
    my @official = [];
    push @official, $hash_ref;
    print Dumper(\@official);
}

__DATA__
1234 2345
1234 2345
3345 4456