怎么用java输出杨辉三角

下面是一个用Java输出杨辉三角的示例代码：

import java.util.*;public class YangHuiTriangle {    public static void main(String[] args) {        Scanner sc = new Scanner(System.in);        System.out.println("请输入要输出的行数：");        int numRows = sc.nextInt();                List<List<Integer>> triangle = generate(numRows);        for (List<Integer> row : triangle) {            for (int num : row) {                System.out.print(num + " ");            }            System.out.println();        }    }        public static List<List<Integer>> generate(int numRows) {        List<List<Integer>> triangle = new ArrayList<>();                if (numRows == 0) {            return triangle;        }                List<Integer> firstRow = new ArrayList<>();        firstRow.add(1);        triangle.add(firstRow);                for (int i = 1; i < numRows; i++) {            List<Integer> prevRow = triangle.get(i - 1);            List<Integer> currRow = new ArrayList<>();                        currRow.add(1);            for (int j = 1; j < i; j++) {                currRow.add(prevRow.get(j - 1) + prevRow.get(j));            }            currRow.add(1);                        triangle.add(currRow);        }                return triangle;    }}

运行这段代码后，输入要输出的行数，程序将会输出相应行数的杨辉三角。