Score : 700 points
We have a board with an H \times W grid.
Each square in the grid is painted in black or white. The square at the i-th row from the top and j-th column from the left is black if the j-th character in S_i is #
, and white if that character is .
.
Snuke can perform the following operation on the grid any number of times:
Then, Snuke draws a rectangle along grid lines. Here, all the squares contained in the rectangle must be painted in black.
Find the maximum possible area of Snuke's rectangle when the operation is performed optimally.
#
and .
.Input is given from Standard Input in the following format:
H W S_1 S_2 : S_H
Print the maximum possible area of Snuke's rectangle.
3 3 ..# ##. .#.
6
If the first row from the top and the third column from the left are inverted, a 2 \times 3 rectangle can be drawn, as shown below:
4 4 .... .... .... ....
16
10 8 ##...#.# ##...#.# ..###.#. #.##.#.# .#..#.#. ..##.#.# ##.#.#.. ...#.#.. ###.#.## ###..###
27