230330 빛의 경로 사이클

public int[] solution(String[] grid) {
    int rows = grid.length;
    int cols = grid[0].length();

    boolean[][][] visited = new boolean[rows][cols][4];
    List<Integer> distances = new ArrayList<>();

    int[] directionsRow = {-1, 0, 1, 0};
    int[] directionsCol = {0, -1, 0, 1};

    for (int row = 0; row < rows; row++) {
        for (int col = 0; col < cols; col++) {
            for (int dir = 0; dir < 4; dir++) {
                if (!visited[row][col][dir]) {
                    int distance = explore(grid, row, col, dir, visited, directionsRow, directionsCol);
                    distances.add(distance);
                }
            }
        }
    }

    return distances.stream().sorted().mapToInt(Integer::intValue).toArray();
}

private static int explore(String[] grid, int row, int col, int dir, boolean[][][] visited, int[] directionsRow, int[] directionsCol) {
    int distance = 0;
    while (!visited[row][col][dir]) {
        distance++;
        visited[row][col][dir] = true;

        char cell = grid[row].charAt(col);
        if (cell == 'L') {
            dir = (dir + 3) % 4;
        } else if (cell == 'R') {
            dir = (dir + 1) % 4;
        }

        row = (row + directionsRow[dir] + grid.length) % grid.length;
        col = (col + directionsCol[dir] + grid[0].length()) % grid[0].length();
    }
    return distance;
}

출처:https://school.programmers.co.kr/learn/courses/30/lessons/86052