comefrom: <awangdev>254. Factor Combinations_2.java
code: private List<List<Integer>> calcFactors(int lastFactor, int num) {
  
          List<List<Integer>> rst = new ArrayList<>();
          int sqrt = (int)Math.sqrt(num);
          for (int i = lastFactor; i <= sqrt; i++) { 
              int remain = num / i;
              if (i * remain == num) rst.add(Arrays.asList(i, remain));
          }
          return rst;
      }
masked: private List < List < Integer >> var_2 ( int var_3 , int var_4 ) {
    List < List < Integer >> var_6 = new ArrayList < > ( ) ;
    int sqrt = ( int ) Math . sqrt ( var_4 ) ;
    for ( int var_9 = var_3 ;
    var_9 <= sqrt ;
    var_9 ++ ) {
      int var_10 = var_4 / var_9 ;
      if ( var_9 * var_10 == var_4 ) var_6 . add ( Arrays . asList ( var_9 , var_10 ) ) ;
    }
    return var_6 ;
  }
  