Package 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 Details

    • Solution

      public Solution()

  • Method Details

    • countBattleships

      public int countBattleships(char[][] board)