무인도 여행 ( Level 2, JavaScript, 연습문제)

const dx = [-1, 0, 1, 0]
const dy = [0, -1, 0, 1]        

const dfs = (maps, visited, x, y, sum) => {
    visited[x][y] = 1
    for (let i = 0; i < 4; i++) {
        const [nx, ny] = [x + dx[i], y + dy[i]]
        if (0 <= nx && nx < maps.length &&
            0 <= ny && ny < maps[0].length &&
            maps[nx][ny] !== 'X' && !visited[nx][ny]) {
            sum += dfs(maps, visited, nx, ny, +maps[nx][ny])
        }
    }
    return sum
}
const solution = (maps) => {
    const res = []
    const [x, y] = [maps.length, maps[0].length]
    const visited = Array.from({ length: x }, () => Array(y).fill(0)) 
    for (let i = 0; i < x; i++) {
        for (let j = 0; j < y; j++) {
            if (maps[i][j] !== 'X' && !visited[i][j]) {
                res.push(dfs(maps, visited, i, j, +maps[i][j]))
            } 
            visited[i][j] = 1
        }
    }
    return res.length ? res.sort((a, b) => a - b) : [-1]
}

dfs