Merge branch 'master' of https://github.com/manwar/perlweeklychallenge-club

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diff --git a/challenge-191/luca-ferrari/postgresql/ch-2.sql b/challenge-191/luca-ferrari/postgresql/ch-2.sql
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+-- Perl Weekly Challenge 191
+-- Task 2
+
+CREATE SCHEMA IF NOT EXISTS pwc191;
+
+CREATE OR REPLACE FUNCTION
+pwc191.task2_plpgsql( n int )
+RETURNS int
+AS $CODE$
+DECLARE
+	cute_counter int := 0;
+	i int;
+	src int[];
+	permutation int[];
+	is_cute bool;
+BEGIN
+
+	FOR i IN 1 .. n LOOP
+	    src = src || i;
+	END LOOP;
+
+
+
+	FOR permutation IN
+	with recursive
+	data as (select src as arr),
+        keys as (select generate_subscripts(d.arr, 1) as rn from data d),
+        cte  as (
+           select d.arr initial_arr, array[d.arr[k.rn]] new_arr, array[k.rn] used_rn
+           from data d
+           cross join keys k
+           union all
+           select initial_arr, c.new_arr || c.initial_arr[k.rn], used_rn || k.rn
+           from cte c
+           inner join keys k on not (k.rn = any(c.used_rn))
+    )
+    select new_arr
+    from cte
+    WHERE array_length( new_arr, 1 ) = n
+    LOOP
+
+	 is_cute := 1;
+	 FOR i IN 1 .. array_length( permutation, 1 ) LOOP
+	 	 IF permutation[i] % i <> 0  THEN
+		    is_cute = false;
+		    EXIT;
+		 END IF;
+	 END LOOP;
+
+	 IF is_cute THEN
+	    cute_counter := cute_counter + 1;
+	 END IF;
+
+	 is_cute := 1;
+	 FOR i IN 1 .. array_length( permutation, 1 ) LOOP
+	 	 IF i % permutation[i] <> 0  THEN
+		    is_cute = false;
+		    EXIT;
+		 END IF;
+	 END LOOP;
+	 IF is_cute THEN
+		 cute_counter := cute_counter + 1;
+	 END IF;
+
+    END LOOP;
+
+
+RETURN cute_counter;
+END
+$CODE$
+LANGUAGE plpgsql;