在n枚外观相同的硬币中，有一枚是假币，并且已知假币与真币的重量不同，但不知道假币与真币相比较轻还是较重。可以通过一架天平来任意比较两组硬币，设计一个高效的算法来检测出这枚假币。-N pieces of the same in the appearance of the coin, there is the ever- counterfeit money, counterfeit money with real money and are known to the weight of differ