| ||John and Brus have a rectangular chessboard with black and white tiles.
Rows and columns of the chessboard are numbered starting from 0.
The cell at row i, column j is black if i+j is even and it is white if i+j is odd.
Some of the cells of the chessboard are occupied by chess pieces.
You are given a String board.
For each i and j, the j-th character of the i-th element (0-based indices) of board is 'X' if the cell in row i, column j of the chessboard contains a chess piece.
Otherwise, the j-th character of the i-th element of board is '.'.
John and Brus also have an infinite supply of L-shaped tiles.
Each tile consists of three squares which are of the same size as the cells of the chessboard.
I.e., each tile looks as follows:
John and Brus want to place some of the tiles onto their chessboard, according to the following rules:
- Each tile may be rotated by any multiple of 90 degrees.
- Each tile must cover exactly three cells of the chessboard.
- Tiles are not allowed to overlap.
- Tiles are not allowed to cover the cells that are already occupied by the chess pieces.
- The corner cell of each tile must cover a black cell of the chessboard.
Return the maximum number of tiles John and Brus can place on the board according to the above rules.
|Method signature:||int find(String board)|
|(be sure your method is public)|
|-||board will contain between 1 and 47 elements, inclusive.|
|-||Each element of board will contain between 1 and 47 characters, inclusive.|
|-||All elements of board will contain the same number of characters.|
|-||Each element of board will consist of only characters 'X' and '.'.|
|Since only one black cell is available, just one tile can be placed on the board.|
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