쿼드 트리 뒤집기 (문제 ID: QUADTREE, 난이도: 하)

문제 참고 : https://algospot.com/judge/problem/read/QUADTREE

algospot.com :: QUADTREE

 

 

예제 입력

4
w
xbwwb
xbwxwbbwb
xxwwwbxwxwbbbwwxxxwwbbbwwwwbb

 

예제 출력

w
xwbbw
xxbwwbbbw
xxwbxwwxbbwwbwbxwbwwxwwwxbbwb

 

 

public static void main(String[] args) {
    System.out.println(solution("xbwwb"));
    System.out.println(solution("xbwxwbbwb"));
    System.out.println(solution("xxwwwbxwxwbbbwwxxxwwbbbwwwwbb"));
}

public static String solution(String treeStr) {
    return reverseTree(treeStr, 0);
}

static String reverseTree(String treeStr, int point) {
    char pointValue = treeStr.charAt(point);
    if(!(pointValue == 'x')) {
        return String.valueOf(pointValue);
    }

    String upperLeft = reverseTree(treeStr, point + 1);
    String upperRight = reverseTree(treeStr, point + 1 + upperLeft.length());
    String lowerLeft = reverseTree(treeStr, point + 1 + upperLeft.length() + upperRight.length());
    String lowerRight = reverseTree(treeStr, point + 1 + upperLeft.length() + upperRight.length() + lowerLeft.length());

    return new StringBuilder("x").append(lowerLeft).append(lowerRight).append(upperLeft).append(upperRight).toString();
}