With whole stock splits (2:1, 3:1, etc), the number of contracts is increased and the strike price is reduced. Therefore, a 2:1 split on a $30 stock results in 2 contracts having a $15 strike (100x1x30 = 100x2x15).
With fractional stock splits (3:2, 5:2, etc), the number of shares covered per contract increases and the strike price is reduced. Therefore, a 3:2 split on a $30 stock results in 1 contract with a $20 strike, covering 150 shares (100x30 = 150x20)