PWC 257

Task 1 Raku done
Task 2 Raku done

Task 1 PL/Perl done
Task 2 PL/Perl done

Task 1 PL/PgSQL done
Task 2 PL/PgSQL done

Task 1 Python done
Task 2 Python done

Task 1 PL/Java done
Task2  PL/java done

21 files changed, 486 insertions, 3 deletions

diff --git a/challenge-257/luca-ferrari/blog-1.txt b/challenge-257/luca-ferrari/blog-1.txt
new file mode 100644
index 0000000000..8a00312c43
--- /dev/null
+++ b/challenge-257/luca-ferrari/blog-1.txt
@@ -0,0 +1 @@
+https://fluca1978.github.io/2024/02/19/PerlWeeklyChallenge257.html#task1
diff --git a/challenge-257/luca-ferrari/blog-10.txt b/challenge-257/luca-ferrari/blog-10.txt
new file mode 100644
index 0000000000..f579c1d471
--- /dev/null
+++ b/challenge-257/luca-ferrari/blog-10.txt
@@ -0,0 +1 @@
+https://fluca1978.github.io/[= date -%]/PerlWeeklyChallenge257.html#task2pljava
diff --git a/challenge-257/luca-ferrari/blog-2.txt b/challenge-257/luca-ferrari/blog-2.txt
new file mode 100644
index 0000000000..704d8eaa14
--- /dev/null
+++ b/challenge-257/luca-ferrari/blog-2.txt
@@ -0,0 +1 @@
+https://fluca1978.github.io/2024/02/19/PerlWeeklyChallenge257.html#task2
diff --git a/challenge-257/luca-ferrari/blog-3.txt b/challenge-257/luca-ferrari/blog-3.txt
new file mode 100644
index 0000000000..8703580f7f
--- /dev/null
+++ b/challenge-257/luca-ferrari/blog-3.txt
@@ -0,0 +1 @@
+https://fluca1978.github.io/2024/02/19/PerlWeeklyChallenge257.html#task1plperl
diff --git a/challenge-257/luca-ferrari/blog-4.txt b/challenge-257/luca-ferrari/blog-4.txt
new file mode 100644
index 0000000000..ddf34db218
--- /dev/null
+++ b/challenge-257/luca-ferrari/blog-4.txt
@@ -0,0 +1 @@
+https://fluca1978.github.io/2024/02/19/PerlWeeklyChallenge257.html#task2plperl
diff --git a/challenge-257/luca-ferrari/blog-5.txt b/challenge-257/luca-ferrari/blog-5.txt
new file mode 100644
index 0000000000..ed61ce5418
--- /dev/null
+++ b/challenge-257/luca-ferrari/blog-5.txt
@@ -0,0 +1 @@
+https://fluca1978.github.io/2024/02/19/PerlWeeklyChallenge257.html#task1plpgsql
diff --git a/challenge-257/luca-ferrari/blog-6.txt b/challenge-257/luca-ferrari/blog-6.txt
new file mode 100644
index 0000000000..b883396dfc
--- /dev/null
+++ b/challenge-257/luca-ferrari/blog-6.txt
@@ -0,0 +1 @@
+https://fluca1978.github.io/2024/02/19/PerlWeeklyChallenge257.html#task2plpgsql
diff --git a/challenge-257/luca-ferrari/blog-7.txt b/challenge-257/luca-ferrari/blog-7.txt
new file mode 100644
index 0000000000..7cd80518b3
--- /dev/null
+++ b/challenge-257/luca-ferrari/blog-7.txt
@@ -0,0 +1 @@
+https://fluca1978.github.io/2024/02/19/PerlWeeklyChallenge257.html#task1python
diff --git a/challenge-257/luca-ferrari/blog-8.txt b/challenge-257/luca-ferrari/blog-8.txt
new file mode 100644
index 0000000000..7aacad87f4
--- /dev/null
+++ b/challenge-257/luca-ferrari/blog-8.txt
@@ -0,0 +1 @@
+https://fluca1978.github.io/2024/02/19/PerlWeeklyChallenge257.html#task2python
diff --git a/challenge-257/luca-ferrari/blog-9.txt b/challenge-257/luca-ferrari/blog-9.txt
new file mode 100644
index 0000000000..00a1afde82
--- /dev/null
+++ b/challenge-257/luca-ferrari/blog-9.txt
@@ -0,0 +1 @@
+https://fluca1978.github.io/2024/02/19/PerlWeeklyChallenge257.html#task1pljava
diff --git a/challenge-257/luca-ferrari/pljava/pom.xml b/challenge-257/luca-ferrari/pljava/pom.xml
index eec35352dc..6fe5f45834 100644
--- a/challenge-257/luca-ferrari/pljava/pom.xml
+++ b/challenge-257/luca-ferrari/pljava/pom.xml
@@ -5,11 +5,11 @@
   <modelVersion>4.0.0</modelVersion>
 
   <groupId>PWC</groupId>
-  <artifactId>PWC256</artifactId>
+  <artifactId>PWC257</artifactId>
   <version>1</version>
 
-  <name>Perl Weekly Challenge 256</name>
-  <description>Implementation of the tasks in PL/Java for PWC 256</description>
+  <name>Perl Weekly Challenge 257</name>
+  <description>Implementation of the tasks in PL/Java for PWC 257</description>
 
   <properties>
     <project.build.sourceEncoding>US-ASCII</project.build.sourceEncoding>
diff --git a/challenge-257/luca-ferrari/pljava/src/main/java/Task1.java b/challenge-257/luca-ferrari/pljava/src/main/java/Task1.java
new file mode 100644
index 0000000000..bfbdaf121b
--- /dev/null
+++ b/challenge-257/luca-ferrari/pljava/src/main/java/Task1.java
@@ -0,0 +1,83 @@
+package PWC257;
+
+/**
+ * PL/Java implementation for PWC 257
+ * Task 1
+ * See <https://perlweeklychallenge.org/blog/perl-weekly-challenge-257>
+ *
+ *
+ * To compile on the local machine:
+
+ $ export JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64/  # if not already set
+ $ mvn clean build
+ $ scp target/PWC257.jar  luca@venkman:/tmp
+
+
+ * To install into PostgreSQL execute:
+
+ select sqlj.install_jar( 'file:///tmp/PWC257.jar', 'PWC257', true );
+
+ select 257.task1_pljava();
+
+ and then to redeploy:
+
+ select sqlj.replace_jar( 'file:///tmp/PWC257.jar', 'PWC257', true );
+
+*/
+
+import org.postgresql.pljava.*;
+import org.postgresql.pljava.annotation.Function;
+import static org.postgresql.pljava.annotation.Function.Effects.IMMUTABLE;
+import static org.postgresql.pljava.annotation.Function.OnNullInput.RETURNS_NULL;
+
+import org.postgresql.pljava.ResultSetProvider;
+import java.sql.ResultSet;
+
+import java.util.*;
+import java.sql.SQLException;
+import java.util.logging.*;
+
+public class Task1 implements ResultSetProvider {
+
+    private final static Logger logger = Logger.getAnonymousLogger();
+
+    @Function( schema = "pwc257",
+	       onNullInput = RETURNS_NULL,
+	       effects = IMMUTABLE )
+    public static final ResultSetProvider task1_pljava( int[] numbers ) throws SQLException {
+	logger.log( Level.INFO, "Entering task1_pljava" );
+	return new Task1( numbers );
+
+    }
+
+    public Task1( int[] nums ) {
+	numbers = nums;
+    }
+
+    private int[] numbers;
+
+    @Override
+    public boolean assignRowValues(ResultSet receiver, int currentRow)
+	throws SQLException {
+
+	if ( currentRow >= numbers.length )
+	    return false;
+
+	int current = numbers[ currentRow  ];
+
+	int count = 0;
+	for ( int other : numbers )
+	    if ( other < current )
+		count++;
+
+	receiver.updateInt( 1, count );
+	return true;
+
+    }
+
+
+
+    @Override
+    public void close() { }
+
+}
diff --git a/challenge-257/luca-ferrari/pljava/src/main/java/Task2.java b/challenge-257/luca-ferrari/pljava/src/main/java/Task2.java
new file mode 100644
index 0000000000..d92f3d5ad4
--- /dev/null
+++ b/challenge-257/luca-ferrari/pljava/src/main/java/Task2.java
@@ -0,0 +1,93 @@
+package PWC257;
+
+/**
+ * PL/Java implementation for PWC 257
+ * Task 1
+ * See <https://perlweeklychallenge.org/blog/perl-weekly-challenge-257>
+ *
+ *
+ * To compile on the local machine:
+
+ $ export JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64/  # if not already set
+ $ mvn clean build
+ $ scp target/PWC257.jar  luca@venkman:/tmp
+
+
+ * To install into PostgreSQL execute:
+
+ select sqlj.install_jar( 'file:///tmp/PWC257.jar', 'PWC257', true );
+
+ select 257.task2_pljava();
+
+ and then to redeploy:
+
+ select sqlj.replace_jar( 'file:///tmp/PWC257.jar', 'PWC257', true );
+
+
+Example of invocation:
+select pwc257.task2_pljava( array[ 1,0,0,0,1,0,0,0,1 ], 3 );
+
+*/
+
+import org.postgresql.pljava.*;
+import org.postgresql.pljava.annotation.Function;
+import static org.postgresql.pljava.annotation.Function.Effects.IMMUTABLE;
+import static org.postgresql.pljava.annotation.Function.OnNullInput.RETURNS_NULL;
+
+import java.util.*;
+import java.sql.SQLException;
+import java.util.logging.*;
+
+public class Task2 {
+    private final static Logger logger = Logger.getAnonymousLogger();
+
+    @Function( schema = "pwc257",
+	       onNullInput = RETURNS_NULL,
+	       effects = IMMUTABLE )
+    public static final boolean task2_pljava( int[] matrix, int cols  ) throws SQLException {
+	logger.log( Level.INFO, "Entering task2_pljava" );
+
+	boolean ok = false;
+	List<Integer> zero_rows = new LinkedList<Integer>();
+	Integer current = null;
+	List<int[]> leadings = new LinkedList<int[]>();
+
+	for ( int row = 0; row < matrix.length / cols ; row++ ) {
+	    current = null;
+
+	    for ( int col = 0; col < cols; col++ ) {
+
+		int element = matrix[ row * cols + col ];
+		if ( element == 0 || current != null )
+		    continue;
+
+		current = element;
+		if ( current != 1 )
+		    return false;
+
+		leadings.add( new int[]{ row, col } );
+
+		if ( leadings.size() <= 1 )
+		    continue;
+
+		if ( leadings.get( leadings.size() - 2 )[ 0 ] == ( leadings.get( leadings.size() - 1 )[ 0 ] - 1 )
+		     && leadings.get( leadings.size() - 2 )[ 1 ] >= leadings.get( leadings.size() - 1 )[ 1 ] )
+		    return false;
+	    }
+
+	    if ( current == null ) {
+		// all zero row
+		zero_rows.add( row );
+
+		if ( zero_rows.size() <= 1 )
+		    continue;
+
+		if ( zero_rows.get( zero_rows.size() - 2 ) != ( zero_rows.get( zero_rows.size() - 1) - 1 ) )
+		    return false;
+	    }
+	}
+
+	return true;
+
+    }
+}
diff --git a/challenge-257/luca-ferrari/plperl/ch-1.plperl b/challenge-257/luca-ferrari/plperl/ch-1.plperl
new file mode 100644
index 0000000000..cd90b8c23a
--- /dev/null
+++ b/challenge-257/luca-ferrari/plperl/ch-1.plperl
@@ -0,0 +1,23 @@
+--
+-- Perl Weekly Challenge 257
+-- Task 1
+-- See <https://perlweeklychallenge.org/blog/perl-weekly-challenge-257>
+--
+
+CREATE SCHEMA IF NOT EXISTS pwc257;
+
+CREATE OR REPLACE FUNCTION
+pwc257.task1_plperl( int[] )
+RETURNS SETOF int
+AS $CODE$
+
+   my ( $numbers ) = @_;
+
+   for my $current ( $numbers->@* ) {
+       return_next( scalar( grep( { $_ < $current } $numbers->@* ) ) );
+   }
+
+   return undef;
+   
+$CODE$
+LANGUAGE plperl;
diff --git a/challenge-257/luca-ferrari/plperl/ch-2.plperl b/challenge-257/luca-ferrari/plperl/ch-2.plperl
new file mode 100644
index 0000000000..bd4a802dd3
--- /dev/null
+++ b/challenge-257/luca-ferrari/plperl/ch-2.plperl
@@ -0,0 +1,57 @@
+--
+-- Perl Weekly Challenge 257
+-- Task 2
+-- See <https://perlweeklychallenge.org/blog/perl-weekly-challenge-257>
+--
+
+CREATE SCHEMA IF NOT EXISTS pwc257;
+
+CREATE OR REPLACE FUNCTION
+pwc257.task2_plperl( int[][] )
+RETURNS bool
+AS $CODE$
+
+   my ( $matrix ) = @_;
+
+   my $ok = 1;
+   my @zero_rows;
+   my @leadings;
+   
+ my $row ( 0 .. $matrix->@* - 1 ) {
+       my $first_in_row = undef;
+       
+       for my $col ( 0 .. $matrix->@* - 1 ) {
+       	   next if $matrix->[ $row ][ $col ] == 0;
+	   next if $first_in_row;
+
+	   $first_in_row = $matrix->[ $row ][ $col ] if ( ! $first_in_row );
+
+	   # the first non-zero value of every row must be a one
+	   $ok = 0 and last if ( $first_in_row != 1 );
+
+           # leading one
+	   push @leadings, { row => $row, col => $col };
+
+       }
+
+       if ( ! $first_in_row ) {
+       	  # the row was filled with zeros
+	  push @zero_rows, $row;
+
+	  next if @zero_rows <= 1;
+	  $ok = 0 and last if ( @zero_rows[ -1 ] != ( $row - 1 ) );
+       }
+       elsif ( $first_in_row == 1 ) {
+       	   next if @leadings <= 1;
+	   $ok = 0 and last if ( @leadings[ -2 ]->{ col } >= @leadings[ -1 ]->{ col }
+	                      || @leadings[ -2 ]->{ row } != @leadings[ -1 ]->{ row } - 1 );
+       }
+
+       return $ok if ! $ok;
+   }
+
+   return $ok;
+   return undef;
+   
+$CODE$
+LANGUAGE plperl;
diff --git a/challenge-257/luca-ferrari/plpgsql/ch-1.sql b/challenge-257/luca-ferrari/plpgsql/ch-1.sql
new file mode 100644
index 0000000000..6f6b967c8d
--- /dev/null
+++ b/challenge-257/luca-ferrari/plpgsql/ch-1.sql
@@ -0,0 +1,19 @@
+--
+-- Perl Weekly Challenge 257
+-- Task 1
+-- See <https://perlweeklychallenge.org/blog/perl-weekly-challenge-257>
+--
+
+CREATE SCHEMA IF NOT EXISTS pwc257;
+
+CREATE OR REPLACE FUNCTION
+pwc257.task1_plpgsql( numbers int[] )
+RETURNS SETOF int
+AS $CODE$
+   select z
+   from unnest( numbers ) v,
+        lateral ( select count(x)
+	          from unnest( numbers ) x
+		  WHERE x < v ) as y(z);
+$CODE$
+LANGUAGE sql;
diff --git a/challenge-257/luca-ferrari/plpgsql/ch-2.sql b/challenge-257/luca-ferrari/plpgsql/ch-2.sql
new file mode 100644
index 0000000000..cb70f5b58c
--- /dev/null
+++ b/challenge-257/luca-ferrari/plpgsql/ch-2.sql
@@ -0,0 +1,15 @@
+--
+-- Perl Weekly Challenge 257
+-- Task 2
+-- See <https://perlweeklychallenge.org/blog/perl-weekly-challenge-257>
+--
+
+CREATE SCHEMA IF NOT EXISTS pwc257;
+
+CREATE OR REPLACE FUNCTION
+pwc257.task2_plpgsql( matrix int[] )
+RETURNS bool
+AS $CODE$
+	select pwc257.task2_plperl( matrix );
+$CODE$
+LANGUAGE sql;
diff --git a/challenge-257/luca-ferrari/python/ch-1.py b/challenge-257/luca-ferrari/python/ch-1.py
new file mode 100644
index 0000000000..29f331e81f
--- /dev/null
+++ b/challenge-257/luca-ferrari/python/ch-1.py
@@ -0,0 +1,25 @@
+#!python
+
+#
+# Perl Weekly Challenge 257
+# Task 1
+#
+# See <https://perlweeklychallenge.org/blog/perl-weekly-challenge-257>
+#
+
+import sys
+
+# task implementation
+# the return value will be printed
+def task_1( args ):
+    output = []
+    numbers = list( map( int, args ) )
+    for current in numbers:
+        output.append( len( list( filter( lambda x: x < current, numbers ) ) ) )
+
+    return output
+
+
+# invoke the main without the command itself
+if __name__ == '__main__':
+    print( task_1( sys.argv[ 1: ] ) )
diff --git a/challenge-257/luca-ferrari/python/ch-2.py b/challenge-257/luca-ferrari/python/ch-2.py
new file mode 100644
index 0000000000..141fbd3da3
--- /dev/null
+++ b/challenge-257/luca-ferrari/python/ch-2.py
@@ -0,0 +1,61 @@
+#!python
+
+#
+# Perl Weekly Challenge 257
+# Task 2
+#
+# See <https://perlweeklychallenge.org/blog/perl-weekly-challenge-257>
+#
+
+import sys
+
+# task implementation
+# the return value will be printed
+def task_2( numbers ):
+
+    ok = False
+    zero_rows = []
+    leadings  = []
+
+    for row in range( 0, len( numbers ) ):
+        first_in_row = None
+
+        for col in range( 0, len( numbers[ row ] ) ):
+            if numbers[ row ][ col ] == 0:
+                continue
+
+            if first_in_row != None:
+                continue
+
+            first_in_row = numbers[ row ][ col ]
+
+
+            if first_in_row != 1:
+                return False
+
+            leadings.append( { 'row' : row, 'col' : col } )
+            if len(leadings) <= 1:
+                continue
+
+            if leadings[ -2 ][ 'row' ] != ( row - 1 ) and leadings[ -2 ][ 'col' ] >= col:
+                return False
+
+        if first_in_row == None:
+            zero_rows.append( row )
+
+            if len( zero_rows ) <= 1:
+                continue
+            if zero_rows[ -2 ] != ( row - 1 ):
+                return False
+        elif first_in_row == 1:
+            if len( leadings ) <= 1:
+                continue
+            if leadings[ -2 ][ 'row' ] != leadings[ -1 ][ 'row' ] -1 and leadings[ -2 ][ 'col' ] >= leadings[ -1 ][ 'col' ]:
+                return False
+
+    return True
+
+
+# invoke the main without the command itself
+if __name__ == '__main__':
+    print( task_2( [ [0,1,0], [0,0,1], [0,0,0] ] ) )
diff --git a/challenge-257/luca-ferrari/raku/ch-1.raku b/challenge-257/luca-ferrari/raku/ch-1.raku
new file mode 100644
index 0000000000..9c4a9b672d
--- /dev/null
+++ b/challenge-257/luca-ferrari/raku/ch-1.raku
@@ -0,0 +1,12 @@
+#!raku
+
+#
+# Perl Weekly Challenge 257
+# Task 1
+#
+# See <https://perlweeklychallenge.org/blog/perl-weekly-challenge-257>
+#
+
+sub MAIN( *@numbers where { @numbers.elems == @numbers.grep( * ~~ Int ).elems } ) {
+    @numbers.map( -> $current { @numbers.grep( * < $current ).elems } ).join( ', ' ).say;
+}
diff --git a/challenge-257/luca-ferrari/raku/ch-2.raku b/challenge-257/luca-ferrari/raku/ch-2.raku
new file mode 100644
index 0000000000..a393c68939
--- /dev/null
+++ b/challenge-257/luca-ferrari/raku/ch-2.raku
@@ -0,0 +1,85 @@
+#!raku
+
+#
+# Perl Weekly Challenge 257
+# Task 2
+#
+# See <https://perlweeklychallenge.org/blog/perl-weekly-challenge-257>
+#
+
+sub MAIN() {
+# 1. If a row does not consist entirely of zeros, then the first
+#    nonzero number in the row is a 1. We call this the leading 1.
+# 2. If there are any rows that consist entirely of zeros, then
+#    they are grouped together at the bottom of the matrix.
+# 3. In any two successive rows that do not consist entirely of zeros,
+#    the leading 1 in the lower row occurs farther to the right than
+#    the leading 1 in the higher row.
+# 4. Each column that contains a leading 1 has zeros everywhere else
+    #    in that column.
+
+    my $M = [
+        [1, 1, 0],
+        [0, 1, 0],
+        [0, 0, 0]
+    ];
+
+    # $M = [
+    #     [0, 1,-2, 0, 1],
+    #     [0, 0, 0, 1, 3],
+    #     [0, 0, 0, 0, 0],
+    #     [0, 0, 0, 0, 0]
+    # ];
+
+    # $M = [
+    #               [0, 1,-2, 0, 1],
+    #               [0, 0, 0, 0, 0],
+    #               [0, 0, 0, 1, 3],
+    #               [0, 0, 0, 0, 0]
+    # ];
+
+    # $M = [
+    #               [1, 0, 0, 4],
+    #               [0, 1, 0, 7],
+    #               [0, 0, 1,-1]
+    #             ];
+    my $ok = True;
+    my @zero-rows;
+    my @leadings;
+    for 0 ..^ $M.elems -> $row {
+	my $first-in-row = Nil;
+
+
+	for 0 ..^ $M[ $row ].elems -> $col {
+	    next if $M[ $row ][ $col ] == 0;
+	    next if $first-in-row;
+
+	    $first-in-row = $M[ $row ][ $col ] if ! $first-in-row;
+
+	    if ( $first-in-row == 1 ) {
+		# leading one
+		@leadings.push: { row => $row, col => $col };
+		# if not other leadings, skip any check
+		next if @leadings.elems <= 1;
+
+		$ok = False and last if ( @leadings[ * - 2 ]<col> >= $col && @leadings[ * - 2 ]<row> != ( $row - 1 ) );
+	    }
+	}
+
+	if ! $first-in-row {
+	    # the row was made by all zeros
+	    @zero-rows.push: $row;
+	    # if this is the first zero row, cannot check anything
+	    next if @zero-rows.elems <= 1;
+	    # this is not the first zero row, so the previous row must be also zero!
+	    $ok = False if @zero-rows[ * - 2 ] != ( $row - 1 );
+	}
+	elsif $first-in-row != 1 {
+	    $ok = False;
+	}
+
+	'0'.say and exit if ( ! $ok );
+    }
+
+    '1'.say; # here everything is fine
+}