/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
        int[] a = {1,2,3,4};
		ArrayList<int[]> list = permutations(a);
		for(int[] s : list){
		for(int i : s){
System.out.print(i);}
System.out.println();}
	}
 
	static ArrayList<int[]> permutations(int[] a) {
    ArrayList<int[]> ret = new ArrayList<int[]>();
    permutation(a, 0, ret);
    return ret;
}
 
public static void permutation(int[] arr, int pos, ArrayList<int[]> list){
    if(arr.length - pos == 1)
        list.add(arr.clone());
    else
        for(int i = pos; i < arr.length; i++){
            swap(arr, pos, i);
            permutation(arr, pos+1, list);
            swap(arr, pos, i);
        }
}
 
public static void swap(int[] arr, int pos1, int pos2){
    int h = arr[pos1];
    arr[pos1] = arr[pos2];
    arr[pos2] = h;
}
}

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