Now, you’re ready to check the image for sea monsters.

The borders of each tile are not part of the actual image; start by removing them.

In the example above, the tiles become:

.#.#..#. ##...#.# #..#####
###....# .#....#. .#......
##.##.## #.#.#..# #####...
###.#### #...#.## ###.#..#
##.#.... #.##.### #...#.##
...##### ###.#... .#####.#
....#..# ...##..# .#.###..
.####... #..#.... .#......

#..#.##. .#..###. #.##....
#.####.. #.####.# .#.###..
###.#.#. ..#.#### ##.#..##
#.####.. ..##..## ######.#
##..##.# ...#...# .#.#.#..
...#..#. .#.#.##. .###.###
.#.#.... #.##.#.. .###.##.
###.#... #..#.##. ######..

.#.#.### .##.##.# ..#.##..
.####.## #.#...## #.#..#.#
..#.#..# ..#.#.#. ####.###
#..####. ..#.#.#. ###.###.
#####..# ####...# ##....##
#.##..#. .#...#.. ####...#
.#.###.. ##..##.. ####.##.
...###.. .##...#. ..#..###

Remove the gaps to form the actual image:

.#.#..#.##...#.##..#####
###....#.#....#..#......
##.##.###.#.#..######...
###.#####...#.#####.#..#
##.#....#.##.####...#.##
...########.#....#####.#
....#..#...##..#.#.###..
.####...#..#.....#......
#..#.##..#..###.#.##....
#.####..#.####.#.#.###..
###.#.#...#.######.#..##
#.####....##..########.#
##..##.#...#...#.#.#.#..
...#..#..#.#.##..###.###
.#.#....#.##.#...###.##.
###.#...#..#.##.######..
.#.#.###.##.##.#..#.##..
.####.###.#...###.#..#.#
..#.#..#..#.#.#.####.###
#..####...#.#.#.###.###.
#####..#####...###....##
#.##..#..#...#..####...#
.#.###..##..##..####.##.
...###...##...#...#..###

Now, you’re ready to search for sea monsters! Because your image is monochrome, a sea monster will look like this:

                  # 
#    ##    ##    ###
 #  #  #  #  #  #   

When looking for this pattern in the image, the spaces can be anything; only the # need to match. Also, you might need to rotate or flip your image before it’s oriented correctly to find sea monsters. In the above image, after flipping and rotating it to the appropriate orientation, there are two sea monsters (marked with O):

.####...#####..#...###..
#####..#..#.#.####..#.#.
.#.#...#.###...#.##.O#..
#.O.##.OO#.#.OO.##.OOO##
..#O.#O#.O##O..O.#O##.##
...#.#..##.##...#..#..##
#.##.#..#.#..#..##.#.#..
.###.##.....#...###.#...
#.####.#.#....##.#..#.#.
##...#..#....#..#...####
..#.##...###..#.#####..#
....#.##.#.#####....#...
..##.##.###.....#.##..#.
#...#...###..####....##.
.#.##...#.##.#.#.###...#
#.###.#..####...##..#...
#.###...#.##...#.##O###.
.O##.#OO.###OO##..OOO##.
..O#.O..O..O.#O##O##.###
#.#..##.########..#..##.
#.#####..#.#...##..#....
#....##..#.#########..##
#...#.....#..##...###.##
#..###....##.#...##.##.#

Determine how rough the waters are in the sea monsters’ habitat by counting the number of # that are not part of a sea monster. In the above example, the habitat’s water roughness is 273.

Assignment

How many # are not part of a sea monster? This is done in the following way:

• Write a static function waterRoughness that takes the pathname (String) of a text file containing a square number of tiles. The function must return the number (int) of hashes (#) in the actual image that are not part of a sea monster.

This static function must be located in the class Submission.

Example

In this interactive session we assume the text file tiles.txt¹ to be located in the current directory.

> Submission.waterRoughness("tiles.txt")
273