十年换你一句好久不见

摘要： D:Lift Problems On the ground floor (floor zero) of a large university building a number of students are wait- ing for a lift. Normally, the lift stop 阅读全文

摘要： B:Button Bashing You recently acquired a new microwave, and noticed that it provides a large number of buttons to be able to quickly specify the time 阅读全文