The idea is to loop through the original array. For each element, either look up or add that element as a key into a hash, and increments that key's value by one. Since Perl's hashes use autovivification, when we try to look up a non-existing key in a hash, that key will be added.

$hash{$_}++ for @array;
[download]

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

my @fruit = qw(
      MANGO APPLE GRAPES MANGO MANGO MANGO
      MANGO APPLES APPLES BANANA CORN APPLES
);

my %fruit;
$fruit{$_}++ for @fruit;

print Dumper \@fruit;
print Dumper \%fruit;
[download]

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)