Jane tries her best to stay fit. Knowing this, her sister decided to play a prank on Jane: after Jane's old scale broke down, her sister got her a new scale that shows the square of a person's weight, instead of the real weight.
Not noticing the change, Jane has been using the scale for a while. One morning she screamed "Oh no! I gained apparentGain pounds!". Given an int apparentGain (the difference between the square of Jane's current weight and the square of her previous weight), return a int containing Jane's possible real weights after the latest measurement, sorted in ascending order.
All weights (displayed and real, previous and current) are positive integers.