'Solve' doesn't always return the optimal solution

[aalok-sathe]

Here's an example of the "optimal" solution being 6, whereas a better solution of 4 moves is possible (I'll give you time to work through it; hint: it involves moving one other robot).

[smack42]

I think that bug is in your code change to support the fifth (silver) robot. Have a look at function make_key and macro MAKE_KEY in file ricochet.c. #9

Please test it again with the original program, without the silver robot.