Go Scoreboard

Given a matrix representing a Go board with the following types: '' - empty, 'w' - white, 'b' - black, return a final score for the winner of the board. The score is just the number of cells that make up its outer shell. Keep in mind, if a structure is surrounded on all sides by the opposite color, its points are forfeit. Follow-up: for the white side, write a function that returns the single empty cell '' that the player should add a 'w' to in order to increase their score the most.