https://leetcode.com/problems/battleships-in-a-board/// 采用的是排除法，看船的最后一个节点public class Solution {    public int countBattleships(char[][] board) {        int rows = board.length;        int cols = rows > 0 ? board[0].length : 0;        if (rows == 0 || cols == 0) {            return 0;        }        int ret = 0;        for (int i=0; i
     
      =rows || board[i+1][j]=='.') &&                            (j+1>=cols || board[i][j+1]=='.')) {                        ret++;                    }                }            }        }        return ret;    }}