Building an array with random numbers

public static Object[] algorithm1(int N)
{
    //DO NOT COUNT IN opCount
    long opCount = 0;
    String fn = "f(N) = [answer]";
    String On = "O(N) = [answer]";
    //BEGIN opCounts
    int[] arr = new int[N];
    Random randGen = new Random(123456789);
    

       return new Object[] { arr, new String[] { fn, On, opCount + "" } };
   }

Use the following method to fill the array For each position in the array, generate a random number between zero and N If N = 10, random numbers should be 0-9 Check if that random number is used in any previous position in the array If it is used anywhere else, generate a new number and try again If it is not used anywhere else, place it into the position and move forward