拼图游戏的最原始版本，中间的next按钮按第一次的时候是计算返回到出事状态的步骤。之后每按一次，便倒着走回去（最少步数）。-The jigsaw puzzle of the most primitive version of the middle of the next button is to calculate the first return to the accident the steps of the state. After each time you press, then ba