899 - Colour Circles

[bryanchris]

I'm keeping getting WA on this problem.

Basically I use breadth-first-search on a graph, in which each vertex is essentially a tuple (a, b) where a and b are the circles where the two counter is. Starting from the final state with one of the counter in the target circle, and keep "backtracking" along the possible move until hitting the starting position (r, s) specified in the problem.

I tested my solution against the two example provided, and also the impossible setting for which the program should return 0 and the game where the target is only one move away.

Did I miss anything?

[brianfry713]

I solved it using a BFS starting from the initial position with a counter in R and S, and ending when either counter reaches T.