✅419. 甲板上的战舰 about like-algorithms HOT 2 OPEN

/**
 * @param {character[][]} board
 * @return {number}
 */
var countBattleships = function(board) {
    let result = 0;
    for (let row = 0; row < board.length; row++) {
        for (let col = 0; col < board[0].length; col++) {
            if (board[row][col] === 'X') {
                result++;
                dfs(row, col);
            }
        }
    }

    function dfs(row, col) {
        if (row < 0 || row >= board.length || col < 0 || col >= board[0].length || board[row][col] === '.') return;
        board[row][col] = '.';
        dfs(row-1, col);
        dfs(row+1, col);
        dfs(row, col-1);
        dfs(row, col+1);
    }

    return result;
};

/**
 * @param {character[][]} board
 * @return {number}
 */
var countBattleships = function(board) {
	const xLen = board.length;
	const yLen = board[0].length;
	let ret = 0;
	for (let x = 0; x < xLen; x++) {
		for (let y = 0; y < yLen; y++) {
			if (board[x][y] === 'X') {
				ret++;
				h(board, x, y, xLen, yLen);
			}
		}
	}
	return ret;
};
function h(board, x, y, xLen, yLen) {
	if (x < 0 || y < 0 || x >= xLen || y >= yLen || board[x][y] === '.') return;
	board[x][y] = '.';
	h(board, x - 1, y, xLen, yLen);
	h(board, x + 1, y, xLen, yLen);
	h(board, x, y - 1, xLen, yLen);
	h(board, x, y + 1, xLen, yLen);
}