import java.util.*; public class BackTrack_Permutation { public static List> generate(int [] arr){ List> result = new ArrayList<>(); backtrack(result,0,arr); return result; } public static void backtrack(List> result , int start, int[] num){ if(start == num.length){ List temp = new ArrayList<>(); for(int i: num) temp.add(i); result.add(temp); } for(int i = start;i> permutations = generate(arr); for(List perm : permutations) { System.out.println(perm); } } }