Sokoban Level 4a

This is one of the last levels of sokoban. Behind the holes is a Treasure Zoo with in one of the three doors a treasure, a bag of holding. There are 18 boulders and 16 pit.

0 boulder
^ pit
@ starting position/downstairs
< upstairs

--------------------------
|@......^^^^^^^^^^^^^^^^.|
|.......----------------.|
-------.------         |.|
 |...........|         |.|
 |.0.0.0.0.0.|         |.|
--------.----|         |.|
|...0.0..0.0.|         |.|
|...0........|         |.|
-----.--------   ------|.|
 |..0.0.0...|  --|.....|.|
 |.....0....|  |.+.....|.|
 |.0.0...0.--  |-|.....|.|
-------.----   |.+.....+.|
|..0.....|     |-|.....|--
|........|     |.+.....|
|...------     --|.....|
-----            -------

Strategy

The following solution solves the level without putting any blocks in an immobile position. Faster solutions which do not necessarily leave every boulder free might exist.

All boulders are replaced by letters so they can be referred to. Moving the boulders is shortened to r for right, l for left, u for up, d for down. An asterisk is used to denote the last move filled a pit (and thus removed the boulder from the game). So Nddrr* means move boulder N two times down and two times to the right into a pit.

--------------------------
|@......^^^^^^^^^^^^^^^^.|
|.......----------------.|
-------.------         |.|
 |...........|         |.|
 |.A.B.C.D.E.|         |.|
--------.----|         |.|
|...F.G..H.I.|         |.|
|...J........|         |.|
-----.--------   ------|.|
 |..K.L.M...|  --|.....|.|
 |.....N....|  |.+.....|.|
 |.O.P...Q.--  |-|.....|.|
-------.----   |.+.....+.|
|..R.....|     |-|.....|--
|........|     |.+.....|
|...------     --|.....|
-----            -------

Store some boulders of the 3th room in the 4th and make some way. Kl

Nrrr
Rrrr
Prrdddlllllurr
Fll
Jrddddrrdddlllllu

--------------------------
|@......^^^^^^^^^^^^^^^^.|
|.......----------------.|
-------.------         |.|
 |...........|         |.|
 |.A.B.C.D.E.|         |.|
--------.----|         |.|
|.F...G..H.I.|         |.|
|............|         |.|
-----.--------   ------|.|
 |.K..L.M...|  --|.....|.|
 |........N.|  |.+.....|.|
 |.O.....Q.--  |-|.....|.|
-------.----   |.+.....+.|
|.J.P.R..|     |-|.....|--
|........|     |.+.....|
|...------     --|.....|
-----            -------

Push G and H out of the way so you can move some of the boulders of the 1st room to the 3th and 4th room.

Gll
Hll
Dldddlllddddr
Crdddlllddd

--------------------------
|@......^^^^^^^^^^^^^^^^.|
|.......----------------.|
-------.------         |.|
 |...........|         |.|
 |.A.B.....E.|         |.|
--------.----|         |.|
|.F.G..H...I.|         |.|
|............|         |.|
-----.--------   ------|.|
 |.K..L.M...|  --|.....|.|
 |...C....N.|  |.+.....|.|
 |.O..D..Q.--  |-|.....|.|
-------.----   |.+.....+.|
|.J.P.R..|     |-|.....|--
|........|     |.+.....|
|...------     --|.....|
-----            -------

It is also possible to push D into the 4th room under J and move C to where D is now if you want some more leeway to move boulders around. Now everything is setup to start filling pits. Cleanup most of room 1 and 2.

Hruuuluuur*
Grrrruuuluuurr*
Frrrrrruuuluuurrr*
Illluuuluuurrrr*
Cuuuurrruuuluuurrrrr*
Krruuurrruuuluuurrrrrr*
Lluuurrruuuluuurrrrrrr*
Mllluuurrruuuluuurrrrrrrr*
Nllllluuuurrruuuluuurrrrrrrrr*

--------------------------
|@...............^^^^^^^.|
|.......----------------.|
-------.------         |.|
 |...........|         |.|
 |.A.B.....E.|         |.|
--------.----|         |.|
|............|         |.|
|............|         |.|
-----.--------   ------|.|
 |..........|  --|.....|.|
 |..........|  |.+.....|.|
 |.O..D..Q.--  |-|.....|.|
-------.----   |.+.....+.|
|.J.P.R..|     |-|.....|--
|........|     |.+.....|
|...------     --|.....|
-----            -------

Now there are only a few boulders left with a lot of space. The boulders in room 4 can be cleared directly, the boulders in room 1 and 3 should first be moved through room 3 and 4 respectively.

Rruuuulluuurrruuuluuurrrrrrrrrr*
Prrruuuulluuurrruuuluuurrrrrrrrrrr*
Jrrrrruuuulluuurrruuuluuurrrrrrrrrrrr*
Drdddlllllurrrrruuuulluuurrruuuluuurrrrrrrrrrrrr*
Brrrdddlllddduuuurrruuuluuurrrrrrrrrrrrrr*
Arrrrrdddlllddduuuurrruuuluuurrrrrrrrrrrrrrr*
Ellldddlllddduuuurrruuuluuurrrrrrrrrrrrrrrr*

--------------------------
|<.......................|
|.......----------------.|
-------.------         |.|
 |...........|         |.|
 |...........|         |.|
--------.----|         |.|
|............|         |.|
|............|         |.|
-----.--------   ------|.|
 |..........|  --|.....|.|
 |..........|  |.+.....|.|
 |.O.....Q.--  |-|.....|.|
-------.----   |.+.....+@|
|........|     |-|.....|--
|........|     |.+.....|
|...------     --|.....|
-----            -------

In the large room behind the door is a zoo. Behind one of the three doors in the zoo is an Elbereth-engraved square with a bag of holding.