[LeetCode]Battleships in a Board 战舰数目

声明：原题目转载自LeetCode，解答部分为原创

Problem ：

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) orNx1 (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:

...XXXXX...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?

Solution：

        思路：用BFS的方法遍历二维矩阵，本题的关键是准确判断图形符合要求的条件。忙碌中，代码略显凌乱，请大家见谅，日后将重新整理。

        代码如下：