In the book "Introduction to Algorithms", second edition, there is the following problem:

Suppose we have some array:

int a[] = {1,2,3,4}

and some random priorities array:

P = {36,3,97,19}

and the goal is to permute the array a randomly using this priorities array.

This is the pseudo code:

PERMUTE-BY-SORTING (A)
1 n ? length[A]
2 for i ? 1 to n
3      do P[i] = RANDOM (1, n 3)
4 sort A, using P as sort keys
5 return A

The result should be the permuted array:

B={2, 4, 1, 3};

I have written this code:

import java.util.*;

public class Permute {

    public static void main (String[] args) {
        Random r = new Random();
        int a[] = new int[] {1,2,3,4};
        int n = a.length;
        int b[] = new int[a.length];
        int p[] = new int[a.length];
        for (int i=0; i<p.length; i++) {
            p[i] = r.nextInt(n*n*n) + 1;
        }

        // for (int i=0;i<p.length;i++){
        // System.out.println(p[i]);
        //}
    }
}

How do I continue?