Merge pull request #10070 from fluca1978/PWC268

PWC 268

1 files changed, 72 insertions, 0 deletions

diff --git a/challenge-268/luca-ferrari/pljava/src/main/java/Task2.java b/challenge-268/luca-ferrari/pljava/src/main/java/Task2.java
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+
+
+
+package PWC268;
+
+/**
+ * PL/Java implementation for PWC 268
+ * Task 2
+ * See <https://perlweeklychallenge.org/blog/perl-weekly-challenge-268>
+ *
+ *
+ * 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/PWC268-1.jar  luca@rachel:/tmp
+
+
+ * To install into PostgreSQL execute:
+
+ select sqlj.install_jar( 'file:///tmp/PWC268-1.jar', 'PWC268', true );
+ select sqlj.set_classpath( 'public', 'PWC268' );
+
+ select pwc268.task2_pljava();
+
+ and then to redeploy:
+
+ select sqlj.replace_jar( 'file:///tmp/PWC268-1.jar', 'PWC268', 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 = "pwc268",
+	       onNullInput = RETURNS_NULL,
+	       effects = IMMUTABLE )
+    public static final int[] task2_pljava( int[] nums ) throws SQLException {
+	logger.log( Level.INFO, "Entering pwc268.task2_pljava" );
+
+	List<Integer> sorted = new LinkedList<Integer>();
+	for ( int i : nums )
+	    sorted.add( i );
+	Collections.sort( nums );
+
+	int[] result = new int[ nums.length ];
+	int index = 0;
+
+	for ( int i = 0; i < sorted.size(); i++ ) {
+	    int left = sorted.get( i );
+	    int right = sorted.get( ++i );
+
+	    result[ index++ ]   = ( left > right ? left : right );
+	    result[ index++ ] = ( left > right ? right : left );
+	}
+
+	return result;
+    }
+}