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+package PWC258;
+
+/**
+ * PL/Java implementation for PWC 258
+ * Task 2
+ * See <https://perlweeklychallenge.org/blog/perl-weekly-challenge-258>
+ *
+ *
+ * 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/PWC258.jar luca@rachel:/tmp
+
+
+ * To install into PostgreSQL execute:
+
+ select sqlj.install_jar( 'file:///tmp/PWC258-1.jar', 'PWC258', true );
+
+ select pwc258.task2_pljava();
+
+ and then to redeploy:
+
+ select sqlj.replace_jar( 'file:///tmp/PWC258-1.jar', 'PWC258', 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 java.util.*;
+import java.util.stream.*;
+import java.sql.SQLException;
+import java.util.logging.*;
+import java.sql.ResultSet;
+import java.sql.Date;
+
+public class Task2 {
+
+ private final static Logger logger = Logger.getAnonymousLogger();
+
+ @Function( schema = "pwc258",
+ onNullInput = RETURNS_NULL,
+ effects = IMMUTABLE )
+ public static final int task2_pljava( int k, int[] nums ) throws SQLException {
+ logger.log( Level.INFO, "Entering task2_pljava" );
+
+ // int sum = 0;
+ // int count = 0;
+ // for ( int i = 0; i < nums.length; i++ ) {
+ // count = 0;
+ // for ( String d : Integer.toBinaryString( i ).split( "" ) )
+ // if ( d.equals( "1" ) )
+ // count++;
+
+
+ // if ( count == k )
+ // sum += nums[ i ];
+ // }
+
+ // return sum
+
+ return IntStream.range( 0, nums.length )
+ .map( current -> {
+ int ones = 0;
+ for ( String d : Integer.toBinaryString( current ).split( "" ) )
+ if ( d.equals( "1" ) )
+ ones ++;
+
+
+ if ( ones == k )
+ return nums[ current ];
+ else
+ return 0;
+
+ } ).sum();
+;
+ }
+}