摘要：
F. New Year Tree You are a programmer and you have a New Year Tree (not the traditional fur tree, though) — a tree of four vertices: one vertex of deg 阅读全文
摘要：
F - Oddly Similar Problem Statement There are $N$ sequences of length $M$, denoted as $A_1, A_2, \ldots, A_N$. The $i$-th sequence is represented by $ 阅读全文