摘要:
In a country, there are a number of cities. Each pair of city is connected by a highway, bi-directional of course. A road-inspector’s task is to trave 阅读全文
摘要:
Description The 15-puzzle has been around for over 100 years; even if you don't know it by that name, you've seen it. It is constructed with 15 slidin 阅读全文