Merge pull request #9737 from fluca1978/PWC260

PWC 260

1 files changed, 75 insertions, 0 deletions

diff --git a/challenge-260/luca-ferrari/pljava/src/main/java/Task1.java b/challenge-260/luca-ferrari/pljava/src/main/java/Task1.java
new file mode 100644
index 0000000000..5f861c3715
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+++ b/challenge-260/luca-ferrari/pljava/src/main/java/Task1.java
@@ -0,0 +1,75 @@
+
+
+
+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;
+
+    }
+}