In article <11*********************@75g2000cwc.googlegroups.c om>,

<sp****@gmail.com> wrote:

What I'm not sure about is the stipulation that the number of buttons

can be no more than 8. Does this make the problem easier ? I don't

see how.

Not sure; there are 109600 single-press solutions for 8 buttons,

and 986409 for 9 buttons. However, these solutions can be broken up

into a pair of counters, one recording the number of buttons

at a time and the other one the solution index within that. If one

does that, then for 8 buttons, the maximum solution index for a

fixed number of buttons is 8! which is 40320 which fits within an

unsigned int even on systems with 16 bit int. For 9 buttons, the

maximum solution index for a fixed number of buttons would be 9!

which is 362880 which would require more than 16 unsigned bits.

As the "quiz" has been around for rather some time, I suspect that

this 16 bit arithmetic limit was considered important at the time.

--

There are some ideas so wrong that only a very intelligent person

could believe in them. -- George Orwell