99클럽 코테 스터디 31일차 TIL - Bad Grass

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function numIslands(grid) {
    if (grid.length === 0) return 0;

    const directions = [
        [-1, 0], [1, 0], [0, -1], [0, 1],
        [-1, -1], [-1, 1], [1, -1], [1, 1]
    ];
    let count = 0;

    function dfs(x, y) {
        if (x < 0 || y < 0 || x >= grid.length || y >= grid[0].length || grid[x][y] === '0') {
            return;
        }
        grid[x][y] = '0'; // Mark this cell as visited by setting it to '0'
        for (let [dx, dy] of directions) {
            dfs(x + dx, y + dy);
        }
    }

    for (let i = 0; i < grid.length; i++) {
        for (let j = 0; j < grid[0].length; j++) {
            if (grid[i][j] !== '0') {
                count++;
                dfs(i, j);
            }
        }
    }
    
    return count;
}