You are given a matrix where each cell can have values

D - your desk
B - Boss's desk (can be multiple)
S - Snack (can be multiple)
. - empty
# - wall

first question -> Find if it's possible to get a snack from your desk without disturbing any boss.
BFS

second question ->
If the snack has a noise value K. K represnt the number of empty spaces the noise can travel through. find if its' possible to get the snack without disturbing any boss' through noise.

sol. first do multisource bfs from All B's and store min distance of a cell from any B's. then do a BFS from D to S such that you do not use any points where dist(cell) <= k from B

third question ->

Find the maximum value of K for which you can get the snack without distrubing any B's.

Binary Search on K with the solution of 2nd.