Merge pull request #1321 from Doomtrain14/master

Added perl5 solution for ch#49-2

1 files changed, 80 insertions, 0 deletions

diff --git a/challenge-049/yet-ebreo/perl5/ch-2.pl b/challenge-049/yet-ebreo/perl5/ch-2.pl
new file mode 100644
index 0000000000..7b8d1ade41
--- /dev/null
+++ b/challenge-049/yet-ebreo/perl5/ch-2.pl
@@ -0,0 +1,80 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use feature 'say';
+
+my $cache = lru->new(3);
+$cache->set(1,3);
+$cache->set(2,5);
+$cache->set(3,7);
+say $cache->get(2);
+say $cache->get(1);
+say $cache->get(4);
+$cache->set(4,9);
+say $cache->get(3);
+
+package lru;
+sub new {
+
+    my $class = shift;
+    #Create a class/package that has
+    #Variable object to hold the cache size/capacity
+    #Hash object to hold key-value pairs
+    #Array object to hold the order of LRU (LRU ... MRU)
+    my $self = {
+        'size'  => shift,
+        'hash'  => {},
+        'order' => []
+    };
+    bless $self, $class;
+    return $self;
+}
+
+sub set {
+    my ($self, $key, $value) = @_;
+    
+    #Delete LRU from hash and update order if
+    #cache is FULL (hash size is equal to cache size)
+    if ((!exists ($self->{hash}{$key})) && (~~keys %{$self->{hash}} >= $self->{size})) {
+        delete $self->{hash}{$self->{order}[0]};
+        shift @{$self->{order}};
+    }
+    
+    #Update order array
+    #If the key already exists in cache remove the key from order array then...
+    if (exists ($self->{hash}{$key})) {
+        @{$self->{order}} = grep  { $_ != $key } @{$self->{order}};
+    } 
+    
+    #put it in last/highest index (Considered as MRU)
+    push @{$self->{order}}, $key;
+
+    #Update hash key-value pair
+    $self->{hash}{$key} = $value;
+}
+
+sub get {
+    my ($self, $key) = @_;
+
+    if (exists $self->{hash}{$key}) {
+        #Update the order of the array same as the one in Set method
+        @{$self->{order}} = grep  { $_ != $key } @{$self->{order}};
+
+        #put it in last/highest index (Considered as MRU)
+        push @{$self->{order}}, $key;
+
+        #Return the value of the given key
+        return $self->{hash}{$key}
+    } else {
+        return -1;
+    }
+
+}
+=begin
+perl .\ch-2.pl
+5
+3
+-1
+-1
+=cut
\ No newline at end of file