欧阳生朵

摘要： DescriptionA network ofmroads connectsNcities (numbered from 1 toN). There may be more than one road connecting one city with another. Some of the roads are paid. There are two ways to pay for travel on a paid roadifrom cityaito citybi:in advance, in a cityci(which may or may not be the same asai);a 阅读全文