为什么我的Pascal的Triangle Java代码无法正常工作？

Question

My question has been recently put on hold, so I decided to ask it again.

I have an assignment where my professor wants us to make Pascal's triangle on Java. He provided us a completed Main class that is supposed to work and we have to use it. We do not have to edit the Main class. The Main class is correct. It calls for the method where we have to write in our code. Also, I provided the correct output and the template of the Pascal class, which has the method I am supposed to fill in.

Here is the main class:

 public class Main 
  {

  public static void main(String[] args) 
  {

    int n = args.length == 1 ? Integer.parseInt(args[0]) : 1;

    for (int i = 1; i <= n; ++i) 
    {
        int[] arr = Pascal.triangle(i);
        System.out.print((i < 10 ? " " : "") + i + ": ");
        for (int j : arr) 
        {
            System.out.print(j + " ");
        }
        System.out.println();
    }
 }
}

My professor wants us to use his template of the Pascal class where we have to write in the code for the triangle method only. This is the only area where we have to write code for the assignment.

 public class Pascal 
 {
   public static int[] triangle(int n) 
   {
     //My code goes here
     return new int[]{0};
   }
 }

The output should be this:

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

Here is my Pascal class code:

 public class Pascal
 {
   public static int[] triangle(int n) 
   {
   int [][] pt = new int[n+1][];

     for (int i = 0; i < n; i++) 
     {
     pt[i] = new int[i + 1];
     pt[i][0] = 1;//sets the position to 1
     pt[i][i] = 1;

      for (int j = 1; j < pt[i].length - 1; j++)
      {
       pt[i][j] = pt[i-1][j-1] + pt[i-1][j];
      }
 }
  return new int[]{0};
 }
} 

My output:

 1: 0 
 1: 10 
 1: 20 
 1: 1 
 1: 0 
 1: 0 

Answer 1

Just return pt[n-1]; instead of a new empty array from the template (you are supposed to remove that line).

With that, it works for me, your algorithm is correct.