java 输入n，输出n行杨辉三角。

以下是 Java 代码：

import java.util.Scanner;

public class YangHuiTriangle {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入要输出的行数：");
        int n = scanner.nextInt();
        int[][] triangle = new int[n][n];
        for (int i = 0; i < n; i++) {
            triangle[i][0] = 1;
            triangle[i][i] = 1;
            for (int j = 1; j < i; j++) {
                triangle[i][j] = triangle[i - 1][j - 1] + triangle[i - 1][j];
            }
        }
        for (int i = 0; i < n; i++) {
            for (int j = 0; j <= i; j++) {
                System.out.print(triangle[i][j] + " ");
            }
            System.out.println();
        }
    }
}

输入样例：

请输入要输出的行数：5

输出样例：

1 
1 1 
1 2 1 
1 3 3 1 
1 4 6 4 1