Leetcode•Apr 11, 2026
Battleships in a Board
Hazrat Ali
Leetcode
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
Solution
var countBattleships = function(board) {
let m = board.length;
let n = board[0].length;
let count = 0;
for (let i = 0; i < m; i++) {
for (let j = 0; j < n; j++) {
if (board[i][j] === 'X') {
if ((i === 0 || board[i - 1][j] !== 'X') &&
(j === 0 || board[i][j - 1] !== 'X')) {
count++;
}
}
}
}
return count;
};