在java中如何用一维数组输出杨辉三角

用一维数组输出杨辉三角

形状如下：

   1
   1   1
   1   2   1
   1   3   3   1
   1   4   6   4   1
   1   5  10  10   5   1
   1   6  15  20  15   6   1
   1   7  21  35  35  21   7   1
   1   8  28  56  70  56  28   8   1
   1   9  36  84 126 126  84  36   9   1

---

public class Yanghui {
    public static void main(String [] argv) {
        int level = 9;
        int[] a = new int[level];
        int[] b = new int[level];
        for (int i = 0; i < level; i++) {
            int[] current;
            int[] last;
            if (0 == i %2) {
                current = a;
                last = b;
            }
            else {
                current = b;
                last = a;
            }

            for (int j = 0; j < i + 1; j++) {
                if (i == 0 || j == 0 || i == j) {
                    current[j] = 1;
                } else {
                    current[j] = last[j - 1] + last[j];
                }
                System.out.print(current[j] + " ");
            }
            System.out.println();
        }
    }
}