/**  * 78. Subsets  * https://leetcode.com/problems/subsets/description/  *  * Given a set of distinct integers, nums, return all possible subsets (the power set). Note: The solution set must not contain duplicate subsets. Example: Input: nums = [1,2,3] Output: [ [3], [1], [2], [1,2,3], [1,3], [2,3], [1,2], [] ]  * */

1 class Solution { 2     fun subsets(A: IntArray): List
     
      
       > { 3         A.sort(); 4         val result = ArrayList
       
        
         >(); 5         helper(result, ArrayList
         
          (), A, 0); 6         return result; 7     } 8  9     fun helper(result: ArrayList
          
           
            >, arr: ArrayList
            
             , A: IntArray, index: Int){10 result.add(ArrayList
             
              (arr));//new reference for arr11 for (i in index..(A.size - 1)) {12 arr.add(A[i]);13 helper(result, arr, A, i + 1);14 arr.removeAt(arr.size - 1);15 }16 }17 }