Collections.shuffle(list) without repetition.

Question

Hello every one,
I am new to Collections. I have an String ArrayList having 3 strings in it. [A, B, C]. Now all i want is 6 permutations.
[A, B, C]
[A, C, B]
[B, A, C]
[B, C, A]
[C, A, B]
[C, B, A]
Here is the simple code i have written. I hard coded the number of permutations as i know the value to make it simple.
The problem is in those 6 permutations, few are being repeated which I dont want
Please help me out with this problem.
import java.util.*;
import java.util.Collections;
import java.util.List;
import java.util.Random;
public class sample {
     public static void main(String args[]) {
          ArrayList<String> list = new ArrayList<String>();
          list.add("A");
          list.add("B");
          list.add("C");
          int permutations = 6;
          for ( int i = 0 ; i < permutations; i++)
Collections.shuffle(list);
          System.out.println(list.toString());
Thanks in advance
aady

Answer 1

hi,
may be this can help you. i found this code in [http://compsci.ca/v3/viewtopic.php?t=5214|http://compsci.ca/v3/viewtopic.php?t=5214] under the user zylum.
the code is used for integers. but i managed to change is to Strings too and it shuffles without REPETITION. :) so i hope this helps:
int[] numbers = new int[52];
int randNumbers = new int[22];
for (int i = 0; i < 52; i ++) numbers[i] = i;
for (int i = 0; i < 52; i ++) {
    int idx = Math.random()*52; //i forgot how to do random in java so im using the action script way which is prolly the same way
    int temp = numbers[idx];
    numbers[idx] = numbers;
numbers[i] = temp;
for (int i = 0; i < 22; i ++) randNumbers[i] = numbers[i];
Edited by: djmlog103 on Apr 2, 2008 9:53 AM
Edited by: djmlog103 on Apr 2, 2008 9:54 AM