摘要：
Going from u to v or from v to u?Time Limit: 2000MSMemory Limit: 65536KTotal Submissions: 11440Accepted: 2929DescriptionIn order to make their sons brave, Jiajia and Wind take them to a big cave. The cave has n rooms, and one-way corridors connecting some rooms. Each time, Wind choose two rooms x an 阅读全文
