import java.util.Arrays;

import java.util.HashSet;

import java.util.Iterator;

import java.util.Set;

/*

 * java实现一串数字的全排列

 * @Author: WinjayYu

 */

public class TestPermutation {

    static int[] arr = { 1, 2, 3, 4 };

    static Set set = new HashSet();

    public static void main(String[] args) {

        new TestPermutation().sort(0,arr.length);

        for(Iterator it = set.iterator(); it.hasNext();) {

            System.out.println(it.next().toString());

        }

    }

    public void sort(int index, int length) {

            int temp;

            set.add(Arrays.toString(arr));

            for (int i = index; i <= length - 1; i++) {

                temp = arr[index];

                arr[index] = arr[i];

                arr[i] = temp;

                sort(index + 1, length);

                temp = arr[index];

                arr[index] = arr[i];

                arr[i] = temp;

            }

    }

}