Help for this page

Select Code to Download

Select or download this
```
$help{$_}++ for @a
```

Select or download this

my @a= (1,2,3,4,5,6,6,5,4,3,2,1);
my %help;
my @wasted_array = map { $help{$_}=1 } @a;
@a = keys %help;
print @wasted_array, "\n", @a;