禁止不能3連線的交換 disallow swaps that don't create chain
禁止不能3連線的交換 disallow swaps that don't create chain

however, the invalid swap will oscillate. I don't want to fix this bug right now.
然而，無效的交換會震盪。暫時不想修理這個bug

stdio2016/shapeclear-html,stdio2016/shapeclear-html,stdio2016/shapeclear-html,stdio2016/shapeclear-html