Question 3
Fog is spreading across Bebrasland. The terrain is a square-cell grid. Fog starts in the marked cells; each hour it spreads to horizontally or vertically adjacent cells, but never into mountain cells. The example shows the initial map, after one hour, and after two hours, respectively.
For the following map, what is the smallest number of hours until fog covers every house?
For the following map, what is the smallest number of hours until fog covers every house?