Task2 in plpgsql

1 files changed, 54 insertions, 0 deletions

diff --git a/challenge-169/luca-ferrari/postgresql/ch-2.sql b/challenge-169/luca-ferrari/postgresql/ch-2.sql
new file mode 100644
index 0000000000..4c791bbab3
--- /dev/null
+++ b/challenge-169/luca-ferrari/postgresql/ch-2.sql
@@ -0,0 +1,54 @@
+-- Perl Weekly Challenge 169
+-- Task 2
+
+CREATE SCHEMA IF NOT EXISTS pwc169;
+
+CREATE OR REPLACE FUNCTION
+pwc169.task2_plpgsql( n int DEFAULT 20 )
+RETURNS SETOF INT
+AS $CODE$
+DECLARE
+        i int;
+        current_min int;
+        current_gcd int;
+        previous_gcd int;
+BEGIN
+
+        FOR i IN 1 .. 999999 LOOP
+
+           WITH bag AS (
+                SELECT f, count(*) AS counter
+                FROM pwc169.compute_factors( i ) f
+                GROUP BY f
+           )
+           SELECT min( counter )
+           INTO current_min
+           FROM bag
+           ;
+
+           IF current_min < 2 THEN
+              CONTINUE;
+           END IF;
+
+           previous_gcd := -1;
+           FOR current_gcd IN  SELECT count(f) FROM pwc169.compute_factors( i ) f GROUP BY f LOOP
+               IF previous_gcd < 0 THEN
+                  previous_gcd := current_gcd;
+                  CONTINUE;
+               END IF;
+
+               previous_gcd := gcd( previous_gcd, current_gcd );
+           END LOOP;
+
+           IF previous_gcd = 1 THEN
+              RETURN NEXT i;
+              IF n = 0 THEN
+                 RETURN;
+              END IF;
+              n := n - 1;
+           END IF;
+        END LOOP;
+RETURN;
+END
+$CODE$
+LANGUAGE plpgsql;