◇第一站◇ 2018HDU多校赛 十场多校赛下来，也算是给一个初中生开了眼界……看着清华一次次AK（默默立下flag），看着自己被同校的高中生完虐，一个蒟蒻只能给dalao们垫脚?  无论如何，这十场多校赛结束了——胆战心惊、士气高涨或是低头沉思，结果无法改变，比结果更有意义的是在比赛中学会了高校赛的团队攻法，以及一些闻所未闻的算法QwQ 不得不说，前5场的比赛状态实在是太差了，可能是不习惯A

Problem Description “The Werewolves” is a popular card game among young people.In the basic game, there are 2 different groups: the werewolves and the villagers. Each player will debate a player th

Problem Description Steve has an integer array a of length n (1-based). He assigned all the elements as zero at the beginning. After that, he made m operations, each of which is to update an interva

Problem Description Anton has a positive integer n, however, it quite looks like a mess, so he wants to make it beautiful after k swaps of digits. Let the decimal representation of n as (x1x2⋯xm)10

Problem Description Kazari remembered that she had an expression s0 before. Definition of expression is given below in Backus–Naur form. ::= | ::= “+” | “*” ::= “0” | ::= “” | ::= “0” | ::= “

Problem Description Little Q and Little T are playing a game on a tree. There are n vertices on the tree, labeled by 1,2,…,n, connected by n−1 bidirectional edges. The i-th vertex has the value of w