1 files changed, 98 insertions, 0 deletions
diff --git a/challenge-169/luca-ferrari/postgresql/ch-1.sql b/challenge-169/luca-ferrari/postgresql/ch-1.sql
new file mode 100644
index 0000000000..a2d04d97dc
--- /dev/null
+++ b/challenge-169/luca-ferrari/postgresql/ch-1.sql
@@ -0,0 +1,98 @@
+-- Perl Weekly Challenge 169
+-- Task 1
+
+CREATE SCHEMA IF NOT EXISTS pwc169;
+
+CREATE OR REPLACE FUNCTION
+pwc169.is_prime( n int )
+RETURNS bool
+AS $CODE$
+DECLARE
+        i int;
+BEGIN
+        FOR i IN 2 .. ( n - 1 ) LOOP
+            IF n % i = 0 THEN
+               RETURN FALSE;
+            END IF;
+        END LOOP;
+
+        RETURN TRUE;
+END
+$CODE$
+LANGUAGE plpgsql;
+
+
+CREATE OR REPLACE FUNCTION
+pwc169.compute_factors( n int )
+RETURNS SETOF INT
+AS $CODE$
+DECLARE
+        i int;
+BEGIN
+
+        FOR i IN 2 .. ( n - 1 ) LOOP
+            IF NOT pwc169.is_prime( i ) THEN
+               CONTINUE;
+            END IF;
+
+            WHILE n % i = 0 LOOP
+                  RETURN NEXT i;
+                  n = n / i;
+            END LOOP;
+        END LOOP;
+
+RETURN;
+END
+$CODE$
+LANGUAGE plpgsql;
+
+
+CREATE OR REPLACE FUNCTION
+pwc169.task1_plpgsql( n int DEFAULT 20 )
+RETURNS SETOF INT
+AS $CODE$
+DECLARE
+        i int;
+        f int;
+        current_length int := 0;
+        current_count  int := 0;
+        ok bool := false;
+        previous_f     int := 0;
+BEGIN
+
+        FOR i IN 2 .. 100000 LOOP
+
+            current_length := 0;
+            current_count  := 0;
+            ok             := true;
+            previous_f     := 0;
+
+            FOR f IN SELECT * FROM pwc169.compute_factors( i ) ORDER BY 1 LOOP
+
+                current_count := current_count + 1;
+                IF current_length = 0 THEN
+                   current_length := length( f::text );
+                END IF;
+
+                IF length( f::text ) <> current_length OR current_count > 2 OR f = previous_f THEN
+                   ok := false;
+                   EXIT;
+                END IF;
+
+                previous_f := f;
+            END LOOP;
+
+            IF ok AND previous_f <> 0 THEN
+
+               RETURN NEXT i;
+               IF n = 0 THEN
+                  RETURN;
+               END IF;
+               n := n - 1;
+            END IF;
+        END LOOP;
+
+RETURN;
+END
+$CODE$
+LANGUAGE plpgsql;