240309 삼각 달팽이

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

	int[][] triangle = new int[n][n];
	int value = 1;

	int x = -1;
	int y = 0;
	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 <= i; 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