Task 2 in PostgreSQL done

1 files changed, 50 insertions, 0 deletions

diff --git a/challenge-145/luca-ferrari/postgresql/ch-2.sql b/challenge-145/luca-ferrari/postgresql/ch-2.sql
new file mode 100644
index 0000000000..0319ca15d8
--- /dev/null
+++ b/challenge-145/luca-ferrari/postgresql/ch-2.sql
@@ -0,0 +1,50 @@
+/**
+testdb=> select * from f_eertree( 'redivider' );
+current_root |  string
+--------------+-----------
+r            | redivider
+e            | edivide
+d            | divid
+i            | ivi
+(4 rows)
+
+testdb=> select * from f_eertree( 'hello' );
+current_root | string
+--------------+--------
+l            | ll
+(1 row)
+
+*/
+CREATE OR REPLACE FUNCTION
+f_eertree( s text )
+RETURNS TABLE( current_root char, string text )
+AS $CODE$
+DECLARE
+        current int;
+        other   int;
+        other_root   char;
+BEGIN
+
+        FOR current IN 1 .. length( s ) LOOP
+           current_root := substring( s FROM current FOR  1 );
+
+           FOR other IN current + 1 .. length( s ) LOOP
+               other_root := substring( s FROM other FOR 1 );
+               IF other_root <> current_root THEN
+                  CONTINUE;
+               END IF;
+
+               string := substring( s, current, other - current + 1 );
+
+               IF string = reverse( string ) THEN
+                  RETURN NEXT;
+               END IF;
+
+           END LOOP;
+        END LOOP;
+
+        RETURN;
+
+END
+$CODE$
+LANGUAGE plpgsql;