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package PWC260;
/**
* PL/Java implementation for PWC 260
* Task 1
* See <https://perlweeklychallenge.org/blog/perl-weekly-challenge-260>
*
*
* 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/PWC260-1.jar luca@rachel:/tmp
* To install into PostgreSQL execute:
select sqlj.install_jar( 'file:///tmp/PWC260-1.jar', 'PWC260', true );
select sqlj.set_classpath( 'public', 'PWC260' );
select pwc260.task2_pljava();
and then to redeploy:
select sqlj.replace_jar( 'file:///tmp/PWC260-1.jar', 'PWC260', 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 Task1 {
private final static Logger logger = Logger.getAnonymousLogger();
@Function( schema = "pwc260",
onNullInput = RETURNS_NULL,
effects = IMMUTABLE )
public static final boolean task1_pljava( int[] nums ) throws SQLException {
logger.log( Level.INFO, "Entering pwc260.task1_pljava" );
List<Integer> numList = new LinkedList<Integer>();
for ( int n : nums )
numList.add( n );
Map<Integer, List<Integer>> bag = new HashMap<Integer, List<Integer>>();
for ( int current : numList ) {
int occurrency = Collections.frequency( numList, current );
bag.putIfAbsent( occurrency, new LinkedList<Integer>() );
if ( ! bag.get( occurrency ).contains( current ) )
bag.get( occurrency ).add( current );
}
for ( int k : bag.keySet() )
if ( bag.get( k ).size() > 1 )
return false;
return true;
}
}
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