Merge branch 'manwar:master' into master

1 files changed, 59 insertions, 0 deletions

diff --git a/challenge-242/luca-ferrari/postgresql/ch-2.sql b/challenge-242/luca-ferrari/postgresql/ch-2.sql
new file mode 100644
index 0000000000..7c71c0cb2f
--- /dev/null
+++ b/challenge-242/luca-ferrari/postgresql/ch-2.sql
@@ -0,0 +1,59 @@
+--
+-- Perl Weekly Challenge 242
+-- Task 2
+--
+-- See <https://perlweeklychallenge.org/blog/perl-weekly-challenge-242/>
+--
+
+CREATE SCHEMA IF NOT EXISTS pwc242;
+
+/*
+estdb=> select pwc242.task2_plpgsql( array[1,0,0,0,0,0,0,1,1]::int[], 3 );
+ task2_plpgsql
+---------------
+ {1,1,0}
+ {1,1,1}
+ {0,0,1}
+(3 rows)
+*/
+CREATE OR REPLACE FUNCTION
+pwc242.task2_plpgsql( matrix int[], l int )
+RETURNS SETOF int[]
+AS $CODE$
+DECLARE
+	current_row text;
+	current int;
+	index int;
+	to_return int;
+	result int[];
+BEGIN
+	index := 1;
+	current_row := '';
+
+	FOREACH current IN ARRAY matrix LOOP
+		current_row := current_row || current::text;
+		IF index = l THEN
+		   -- the row is now complete, flip and split
+		   result := array[]::int[];
+		   FOREACH to_return IN ARRAY regexp_split_to_array( reverse( current_row ), '' ) LOOP
+		   	   IF to_return = 1 THEN
+			      result := array_append( result, 0 );
+			   ELSE
+			      result := array_append( result, 1 );
+			   END IF;
+		   END LOOP;
+
+		   RETURN NEXT result;
+
+		   -- start over
+		   current_row := '';
+		   index := 1;
+		ELSE
+    		   index := index + 1;
+		END IF;
+	END LOOP;
+
+	RETURN;
+END
+$CODE$
+LANGUAGE plpgsql;