PWC 253

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
Task 2 PL/Java done

1 files changed, 75 insertions, 0 deletions

diff --git a/challenge-253/luca-ferrari/pljava/src/main/java/Task2.java b/challenge-253/luca-ferrari/pljava/src/main/java/Task2.java
new file mode 100644
index 0000000000..9afa1e555f
--- /dev/null
+++ b/challenge-253/luca-ferrari/pljava/src/main/java/Task2.java
@@ -0,0 +1,75 @@
+package PWC253;
+
+/**
+ * PL/Java implementation for PWC 253
+ * Task 2
+ * See <https://perlweeklychallenge.org/blog/perl-weekly-challenge-253>
+ *
+ * To install into PostgreSQL execute:
+
+ select sqlj.install_jar( 'file:///tmp/PWC253.1.jar', 'PWC253', true );
+ select sqlj.set_classpath( 'public', 'PWC253' );
+
+ select task$tn_pljava();
+
+*/
+
+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.*;
+
+/*
+  example of invocation
+
+  java=# select task2_pljava(  4  , array[
+                   [1, 0, 0, 0],
+                   [1, 1, 1, 1],
+                   [1, 0, 0, 0],
+                   [1, 0, 0, 0]
+                 ] );
+ task2_pljava
+--------------
+ {0,2,3,1}
+(1 row)
+
+
+*/
+public class Task2 {
+
+       @Function( onNullInput = RETURNS_NULL, effects = IMMUTABLE )
+       public static final Integer[] task2_pljava( int size, int[] matrix ) throws Exception {
+	   int row_index = 0;
+	   Map<Integer, List<Integer>> ones = new HashMap<Integer, List<Integer>>();
+
+	   int number_of_ones = 0;
+
+	   for ( int i = 0; i < matrix.length; i++ ) {
+	       number_of_ones += matrix[ i ];
+	       if ( ( i + 1 ) % size == 0 || i == matrix.length ) {
+
+		   if ( ! ones.containsKey( number_of_ones ) )
+		       ones.put( number_of_ones, new LinkedList<Integer>() );
+
+		   ones.get( number_of_ones ).add( row_index++ );
+		   number_of_ones = 0;
+	       }
+
+
+	   }
+
+	   List<Integer> keys = new LinkedList<Integer>( ones.keySet() );
+	   Collections.sort( keys );
+
+	   List<Integer> result = new LinkedList<Integer>();
+	   for ( int k : keys ) {
+	       List<Integer> values = ones.get( k );
+	       Collections.sort( values );
+	       result.addAll( values );
+	   }
+
+	   return result.toArray( new Integer[ result.size() ] );
+       }
+}