<awangdev>448. Find All Numbers Disappeared in an Array_2.java
public List<Integer> findDisappearedNumbers(int[] nums) {
        final List<Integer> rst = new ArrayList<Integer>();
        if (nums == null || nums.length == 0) return rst;
            
        for (int i = 0; i < nums.length; i++) {
            int desiredIndex = Math.abs(nums[i]) - 1;
            nums[desiredIndex] = -Math.abs(nums[desiredIndex]); 
        }

        for (int i = 0; i < nums.length; i++) {
            if (nums[i] > 0) rst.add(i + 1);
        }
        
        return rst;
    }
public List < Integer > var_1 ( int [ ] var_2 ) {
  final List < Integer > var_5 = new ArrayList < Integer > ( ) ;
  if ( var_2 == null || var_2 . length == 0 ) return var_5 ;
  for ( int var_9 = 0 ;
  var_9 < var_2 . length ;
  var_9 ++ ) {
    int var_13 = Math . abs ( var_2 [ var_9 ] ) - 1 ;
    var_2 [ var_13 ] = - Math . abs ( var_2 [ var_13 ] ) ;
  }
  for ( int var_9 = 0 ;
  var_9 < var_2 . length ;
  var_9 ++ ) {
    if ( var_2 [ var_9 ] > 0 ) var_5 . add ( var_9 + 1 ) ;
  }
  return var_5 ;
}
