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2152: 聪聪可可Time Limit: 3 Sec Memory Limit: 259 MB Submit: 924 Solved: 487 [Submit][Status][Discuss] Description聪聪和可可是兄弟俩，他们俩经常为了一些琐事打起来，例如家中只剩下最后一根冰棍而两人都想吃、两个人都想玩儿电脑（可是他们家只有一台电脑）……遇到这种问题，一般情况下石头剪刀布

TreeTime Limit: 1000MS Memory Limit: 30000K Total Submissions: 13068 Accepted: 4195 DescriptionGive a tree with n vertices,each edge has a length(positive integer less than 1001). Defin

Prime Distance On Tree题目链接：https://www.codechef.com/problems/PRIMEDSTProblem description.You are given a tree. If we select 2 distinct nodes uniformly at random, what’s the probability that the distanc