230529 삼각 달팽이

public int[] solution(int n) {
    int[] answer = new int[n * (n + 1) / 2];
    int[][] triangle = new int[n][n];

    int x = -1;
    int y = 0;
    int value = 1;

    for (int i = 0; i < n; i++) {
        for (int j = i; j < n; j++) {
            if (i % 3 == 0) {
                x++;
            } else if (i % 3 == 1) {
                y++;
            } else if (i % 3 == 2) {
                x--;
                y--;
            }
            triangle[x][y] = value++;
        }
    }

    int index = 0;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            if (triangle[i][j] == 0)
                break;
            answer[index++] = triangle[i][j];
        }
    }

    return answer;
}

출처:https://school.programmers.co.kr/learn/courses/30/lessons/68645