11569: ABC383 - B - Humidifier 2
Description
The AtCoder company office can be represented as a grid of $H$ rows and $W$ columns. Let $(i, j)$ denote the cell at the $i$-th row from the top and $j$-th column from the left.
The state of each cell is represented by a character $S_{i,j}$. If $S_{i,j}$ is #
, that cell contains a desk; if $S_{i,j}$ is .
, that cell is a floor. It is guaranteed that there are at least two floor cells.
You will choose two distinct floor cells and place a humidifier on each.
After placing the humidifiers, a cell $(i,j)$ is humidified if and only if it is within a Manhattan distance $D$ from at least one of the humidifier cells $(i',j')$. The Manhattan distance between $(i,j)$ and $(i',j')$ is defined as $|i - i'| + |j - j'|$. Note that any floor cell on which a humidifier is placed is always humidified.
Find the maximum possible number of humidified floor cells.
Input
The input is given from Standard Input in the following format:
$H$ $W$ $D$
$S_{1,1}$$S_{1,2}$$\cdots$$S_{1,W}$
$S_{2,1}$$S_{2,2}$$\cdots$$S_{2,W}$
$\vdots$
$S_{H,1}$$S_{H,2}$$\cdots$$S_{H,W}$
Output
Print the answer.
Constraints
- $1 \leq H \leq 10$
- $1 \leq W \leq 10$
- $2 \leq H \times W$
- $0 \leq D \leq H+W-2$
- $H,W,D$ are integers.
- $S_{i,j}$ is
#
or.
. $(1 \leq i \leq H, 1 \leq j \leq W)$ - There are at least two floor cells.
Sample 1 Input
2 5 1
.###.
.#.##
Sample 1 Output
3
When placing humidifiers on $(1,1)$ and $(1,5)$:
- From the humidifier on $(1,1)$, two cells $(1,1)$ and $(2,1)$ are humidified.
- From the humidifier on $(1,5)$, one cell $(1,5)$ is humidified.
In total, three cells are humidified. No configuration can humidify four or more floor cells, so the answer is $3$.
Sample 2 Input
5 5 2
.#.#.
.....
.#.#.
#.#.#
.....
Sample 2 Output
15
When placing humidifiers on $(2,4)$ and $(5,3)$, $15$ floor cells are humidified.
Sample 3 Input
4 4 2
....
.##.
.##.
....
Sample 3 Output
10