g0401_0500.s0419_battleships_in_a_board

Class Solution

java.lang.Object

g0401_0500.s0419_battleships_in_a_board.Solution

public class Solution
extends Object

419 - Battleships in a Board.

Medium

Given an m x n matrix board where each cell is a battleship 'X' or empty '.', return the number of the battleships on board.

Battleships can only be placed horizontally or vertically on board. In other words, they can only be made of the shape 1 x k (1 row, k columns) or k x 1 (k rows, 1 column), where k can be of any size. At least one horizontal or vertical cell separates between two battleships (i.e., there are no adjacent battleships).

Example 1:

Input: board = [[“X”,“.”,“.”,“X”],[“.”,“.”,“.”,“X”],[“.”,“.”,“.”,“X”]]

Output: 2

Example 2:

Input: board = [[“.”]]

Output: 0

Constraints:

• m == board.length
• n == board[i].length
• 1 <= m, n <= 200
• board[i][j] is either '.' or 'X'.

Follow up: Could you do it in one-pass, using only O(1) extra memory and without modifying the values board?

Constructor Summary

Constructors

Constructor and Description
Solution()

Method Summary

Modifier and Type	Method and Description
int	countBattleships(char[][] board)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Solution

public Solution()

Method Detail

countBattleships

public int countBattleships(char[][] board)