每点专题
【Codeforces Round 362 (Div 2)D】【树的遍历 概率均分思想】Puzzles 兄弟节点的等概率遍历下 树的遍历每点期望时间戳
D. Puzzles time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Barney lives in country USC (United States of Charzeh). USC h