※ 引述《mckey (相信台湾坚持改革￾  )》之铭言： : 第一题就是说谎和诚实的地藏王菩萨题目 : 到 inference 版... 很久之前...有一连串讨论... : 基本上...不可能只用一个问题就可以问出来.. : 除非先界定什麽叫做 "one question" : 例如"if... then..." 算是"one question"吗?? : 如果可以.. 那此题就有解了... 其实可以不必在字面上打转 第一 "if... then...?" 就是一个问题 为什麽那是一个问题呢? 因为它只期待一个答案 (村民只会回答你yes or no) 第二 事实上你不要用if then也可以问到你想要问的 回原PO 你可以问 "如果我问一个永远说谎的村民 他会指这条路吗?" 或 "永远说谎的村民会指这条路给我吗?" : 第二题题目 : If Fred 不是最高薪 --> Janice 是最高薪 : If Janice 不是最低薪 --> Maggie 是最高薪 : 由此可见.. Fred 是最高薪.. 否则这两项fact 互相矛盾 : 再来 如果 J 不是最低薪.. 则M和F会互相矛盾 : 所以..J 是最低薪 : 答案 F > M > J 以 F J M 代表三人, 1 2 3 代表排序 原提目改写成 if ( F = 2 or 3) {J = 1}; if ( J = 1 or 2) {M = 1}; 推理 case 1: 假设 J = 1, 则根据第二条规则, M = 1, 和假设相悖. case 2: 假设 M = 1, 则 F = 2 or 3, 根据第一条规则, J = 1, 和假设相悖. case 3: 假设 F = 1, (事实上其他两者已被排除 这个假设一定正确) 再假设 J = 2, 根据第二条规则, M = 2, 和假设相悖. 故得知 F = 1, M = 2, J = 3. : ※ 引述《l314 (红虫)》之铭言： : : 两题皆来自<<Discrete Mathematics and its applications) : : 请高手们指导...orz : : 1.Each inhabitant of a remote village always tells the truth or always lies. : : A villager will only give a "yes" or a "no" response to a question a tourist : : asks. Suppose you are a tourist visiting this area and come to a fork in : : the road. One branch leads to the ruins you want to visit; the other branch : : leads deep into the jungle. A villager is standing at the fork in the road. : : What one question can you ask th villager to determine which branch to take? : : 2.Steve would like to determine the relative salaries of three coworkers : : using two facts. First, he knows that if Fred is not the highest paid of : : the three, then Janice is. Second, he knows that if Janice is not the lowest : : paid, then Maggie is paid the most. Is it possible to determine the relative : : salaried of Fred,Maggie, and Janice from what Steve knows? If so,who is paid : : the most and who the least? Explain your reasoning. --

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