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

1 files changed, 93 insertions, 0 deletions

diff --git a/challenge-257/luca-ferrari/pljava/src/main/java/Task2.java b/challenge-257/luca-ferrari/pljava/src/main/java/Task2.java
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index 0000000000..d92f3d5ad4
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@@ -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;
+
+    }
+}