Asymmetric Digital Print triangle

import java.util.Scanner;

public class Da_Yin_San_Jiao_Xing {
  public static void main(String[] args) {
       Scanner sc=new Scanner(System.in);
   
       System.out.print("请输入你要打印三角形的行数:");
       int n=sc.nextInt();
       int i,j,k,f;
       for(i=1;i<=n;i++) {
   
       for(j=1;j<=n-i;j++)
       System.out.print(" ");
    
       for(k=1;k<=i;k++) 
       System.out.print(k);
    
       for(f=i-1;f>=1;f--) 
       System.out.print(f);
     
       System.out.println();
   }
  }
}

结果显示：
请输入你要打印三角形的行数:6
     1
    121
   12321
  1234321
 123454321
12345654321