230420 무인도 여행

public static int[] solution(String[] maps) {
    boolean[][] visited = new boolean[maps.length][maps[0].length()];
    List<Integer> territories = new ArrayList<>();

    for (int i = 0; i < maps.length; i++) {
        for (int j = 0; j < maps[i].length(); j++) {
            int territorySize = getTerritorySize(i, j, visited, maps);
            if (territorySize > 0) {
                territories.add(territorySize);
            }
        }
    }

    Collections.sort(territories);
    return territories.isEmpty() ? new int[] { -1 } : territories.stream().mapToInt(Integer::intValue).toArray();
}

private static int getTerritorySize(int i, int j, boolean[][] visited, String[] maps) {
    if (i < 0 || j < 0 || i >= visited.length || j >= visited[0].length || visited[i][j]
            || maps[i].charAt(j) == 'X') {
        return 0;
    }

    visited[i][j] = true;
    int territorySize = maps[i].charAt(j) - '0';
    territorySize += getTerritorySize(i - 1, j, visited, maps);
    territorySize += getTerritorySize(i + 1, j, visited, maps);
    territorySize += getTerritorySize(i, j - 1, visited, maps);
    territorySize += getTerritorySize(i, j + 1, visited, maps);
    return territorySize;
}

출처:https://school.programmers.co.kr/learn/courses/30/lessons/154540