awesomese15 / 21dayschallenge Goto Github PK

        List<List<Integer>> answer = new ArrayList<>();
       List<Integer> c = new ArrayList<>(nums.length);
       for(int i:nums){
           c.add(i);
       }
       permute(c, new ArrayList<>(),answer);
       return answer;  
   }
     public static void permute(List<Integer> c, List<Integer> d, List<List<Integer>> answer){
       if(c.isEmpty()){
           answer.add(d);
       }
       for (int i = 0; i < c.size(); i++) {
           List<Integer> nc = new ArrayList<>(c);
           List<Integer> decision = new ArrayList<>(d);
           decision.add(nc.remove(i));
           permute(nc,decision,answer);
       }
   }```