my @array = (
    'a39e432b46dd245ab73ff64fc65b17497ec9ae3d date',
    'a39e432b46dd245ab73ff64fc6asdfijijsdkksdjfks date2',
    'a39e432b46dd245ab73ff64fc6asdfijijsdkksdjfks date3',
);

my %hash = map{ reverse split / /, $_ }@array;

for my $date ( sort keys %hash ){
    print $date,"\n";
}