There are 9 cities.
The ciities ar ordered from 1 to 9 and they are always visited in order from 1 to 9.
From city n to city n+1 there are 4 routes, let's call them 1, 2, 3 and 4 . The distances doesn't matter.
There are 4^8 possible routes from city 1 to city 9.
Is it possible to find out the minimum number of ways to go from city 1 to city 9, such that the route would differ at one and only one segment from the one considered to be the right route?
In other words:
Possible vectors:
(1,1,1,1,1,1,1,1)
(1,1,1,1,1,1,1,2)
(1,1,1,1,1,1,1,4)
(1,1,1,1,1,1,2,1)
(1,1,1,1,1,1,2,2)
.
.
.
(4,4,4,4,4,4,4,4)
Person A chooses any of those. What is the minimum number of vectors person B must choose, to be sure that there is a difference in one and only one place(at most) compared to person A:s vector?