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Given an 2D board, count how many battleships are in it. The battleships are represented with
'X's, empty slots are represented with
'.'s. You may assume the
following rules:
- You receive a valid board, made of only battleships or empty slots.
- Battleships can only be placed horizontally or vertically. In other words, they can only
be made of the shape
1xN (1 row, N columns) or Nx1 (N rows, 1
column), where N can be of any size.
- At least one horizontal or vertical cell separates between two battleships - there are
no adjacent battleships.
Example:
X..X
...X
...X
In the above board there are 2 battleships.
Invalid Example:
...X
XXXX
...X
This is an invalid board that you will not receive - as battleships will always have a cell
separating between them.
Follow up:
Could you do it in one-pass, using only O(1) extra memory
and without modifying the value of the board?
Difficulty:
Medium
Lock:
Normal
All contents and pictures on this website come from the Internet and are updated regularly every week. They are for personal study and research only, and should not be used for commercial purposes. Thank you for your cooperation.