``` 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 ``` ```package algs22; import stdlib.*; import java.security.SecureRandom; /* *********************************************************************** * Compilation: javac SecureShuffle.java * Execution: java SecureShuffle < list.txt * * Reads in a list of strings and prints them in random order. * Our shuffling algorithm guarantees to rearrange the elements * in uniformly random order, under the assumption that Math.random() * generates independent and uniformly distributed numbers between * 0 and 1. * * % more cards.txt * 2C 3C 4C 5C 6C 7C 8C 9C 10C JC QC KC AC * 2D 3D 4D 5D 6D 7D 8D 9D 10D JD QD KD AD * 2H 3H 4H 5H 6H 7H 8H 9H 10H JH QH KH AH * 2S 3S 4S 5S 6S 7S 8S 9S 10S JS QS KS AS * * % java Shuffle < cards.txt * 6H * 9C * 8H * 7C * JS * ... * KH * *************************************************************************/ public class XSecureShuffle { public static void main(String[] args) { // read in the data String[] a = StdIn.readAll().split("\\s+"); int N = a.length; // create random array of real numbers between 0 and 1 SecureRandom random = new SecureRandom(); Double[] r = new Double[N]; for (int i = 0; i < N; i++) { r[i] = random.nextDouble(); } // shuffle and get resulting permutation int[] index = Merge.indexSort(r); // print permutation for (int i = 0; i < N; i++) StdOut.println(a[index[i]]); } } ```