有N个硬币，含 1 枚伪币 （伪币质量与真币质量不一样，真币质量都相同），此程序可以花费平均最少的时间找到伪币(There are N coins, 1 counterfeit coins (coins and coin quality really different quality, the quality of real coins are the same), this program can spend the least time to find the average)