Task 1 and 2 done in Pl/Perl

2 files changed, 83 insertions, 0 deletions

diff --git a/challenge-156/luca-ferrari/postgresql/ch-1.sql b/challenge-156/luca-ferrari/postgresql/ch-1.sql
new file mode 100644
index 0000000000..70a4513be3
--- /dev/null
+++ b/challenge-156/luca-ferrari/postgresql/ch-1.sql
@@ -0,0 +1,35 @@
+CREATE SCHEMA IF NOT EXISTS pwc156;
+
+CREATE OR REPLACE FUNCTION
+pwc156.is_prime( int )
+RETURNS bool
+AS $CODE$
+   return 0 if $_[0] <= 1;
+   for my $i ( 2 .. $_[0] - 1 ) {
+       return 0 if $_[0] % $i == 0;
+   }
+
+   return 1;
+$CODE$
+LANGUAGE plperl;
+
+
+CREATE OR REPLACE FUNCTION
+pwc156.sumbits( int[] )
+RETURNS int
+AS $CODE$
+   my $sum = 0;
+   for my $bit ( @{$_[0]} ) {
+       $sum += $bit;
+   }
+
+   return $sum;
+$CODE$
+LANGUAGE plperl;
+
+
+
+SELECT n
+FROM generate_series( 1, 1000 ) n
+WHERE pwc156.is_prime( pwc156.sumbits( regexp_split_to_array( n::bit(10)::text, '' )::int[] ) )
+LIMIT 10;
diff --git a/challenge-156/luca-ferrari/postgresql/ch-2.sql b/challenge-156/luca-ferrari/postgresql/ch-2.sql
new file mode 100644
index 0000000000..ac9d22739c
--- /dev/null
+++ b/challenge-156/luca-ferrari/postgresql/ch-2.sql
@@ -0,0 +1,48 @@
+CREATE SCHEMA IF NOT EXISTS pwc156;
+
+CREATE OR REPLACE FUNCTION
+pwc156.weird( int )
+RETURNS bool
+AS $CODE$
+
+use Algorithm::Knapsack;
+my @divisors;
+
+for my $i ( 2 .. $_[0] - 1 ) {
+   push @divisors, $i if $_[0] % $i == 0;
+}
+
+my $sum = 0;
+for my $i ( @divisors ) {
+   $sum += $i;
+}
+
+
+return 0 if $sum <= $_[0];
+
+my $knapsack = Algorithm::Knapsack->new(
+    capacity => $_[0],
+    weights  => \@divisors,
+);
+ 
+$knapsack->compute();
+ 
+foreach my $solution ($knapsack->solutions()) {
+    my @founds = @divisors[ $solution->@* ];
+    my $sum = 0;
+    $sum += $_ for ( @founds );
+    return 0 if $sum == $_[0];
+ 
+}
+
+
+return 1;
+$CODE$
+LANGUAGE plperlu;
+
+
+
+
+SELECT n
+FROM generate_series( 1, 100 ) n
+WHERE pwc156.weird( n );