To exit a room, you must open eight doors, that are initially closed. There are nine orbs that act on the doors, as follows:

Orb 1: Toggle door 1 (that is, close it if open, or open it if closed), open door 3 (if already open, leave it that way), and close door 5 (if already closed, leave it that way)
Orb 2: Open 3, close 4, open 7
Orb 3: Toggle 3, close 7, open 8
Orb 4: Open 1, open 3, toggle 5
Orb 5: Close 1, open 4
Orb 6: Toggle 2, open 3, close 5, open 6
Orb 7: Toggle 4 and 5
Orb 8: Open 3, close 7
Orb 9: Close 8

What is the shortest sequence of orbs you must touch in order to get all doors open?

This puzzle appears on level 3 of the "Deadly Rooms of Death (Architect's Edition)" game, also known as "DROD - King Dugan's Dungeon".

The only way to get doors 8, 7, and 6 open are to use Orbs 3, 2, and 6 respectively. So use those three, but in the order of 6, 3, 2. This gives:

    1   2   3   4   5   6   7   8

    /   /   /   /   /   /   /   /

6   /   O   O   /   /   O   /   /

3   /   O   /   /   /   O   /   O

2   /   O   O   /   /   O   O   O

 

Then use orbs 5 and 4 to open the rest.

    1   2   3   4   5   6   7   8

    /   O   O   /   /   O   O   O

5   /   O   O   O   /   O   O   O

4   O   O   O   O   O   O   O   O

 

Five orbs.   I think it is MUCH tougher if you have to figure out the orb door relationships.

Edited on September 29, 2006, 3:18 pm

Posted by Leming on 2006-09-29 15:14:44