삼각 달팽이

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

import java.util.*;
class Solution {
    public int[] solution(int n) {
        int[][] triangle = new int[n][];
        for (int i = 0; i < n; i++) {
            triangle[i] = new int[i + 1];
        }
        
        int number = 1;
        int x = 0, y = 0;
        
        for (int i = 0; i < n; i++) {
            // Down
            while (x < n && triangle[x][y] == 0) {
                triangle[x++][y] = number++;
            }
            x--; y++;
            
            // Right
            while (y < triangle[x].length && triangle[x][y] == 0) {
                triangle[x][y++] = number++;
            }
            x--; y -= 2;
            
            // Up
            while (x >= 0 && triangle[x][y] == 0) {
                triangle[x--][y--] = number++;
            }
            x += 2; y++;
        }
        
        List<Integer> result = new ArrayList<>();
        for (int[] row : triangle) {
            for (int val : row) {
                result.add(val);
            }
        }
        
        int[] answer = new int[result.size()];
        for (int i = 0; i < result.size(); i++) {
            answer[i] = result.get(i);
        }
        
        return answer;
    
    }
}