Thinking Step 3: 推理第二个人。他听到了第一个人的话，推断出第一个人想要。如果第二个人自己不想要，他会说“不”。他说“不知道”，说明他自己也想要，但他不确定第三个人。
"And God called the light Day, and the darkness he called Night. And the evening and the morning were the first day."。业内人士推荐91视频作为进阶阅读
function consoleLog(messageStartIndex, messageLength) {，详情可参考服务器推荐
Shortcut Pre-calculation: For the most commonly used speed profiles, the travel costs (time/distance) for shortcuts between border points within each cluster are pre-calculated and stored. (Each border point effectively has an "entry" and "exit" aspect for directed travel).，更多细节参见51吃瓜