摘要：
Polycarp is a beginner programmer. He is studying how to use a command line. Polycarp faced the following problem. There are n files in a directory an 阅读全文
摘要：
A group of n friends enjoys playing popular video game Toda 2. There is a rating system describing skill level of each player, initially the rating of 阅读全文
摘要：
A. Links and Pearls 题解：~~~没啥说的，没有pearls也算YES！！！ B. Marlin 题解：k是偶数，好办。k是奇数，分类讨论，如果k<=n-2，放在中间。如果k>n-2，第三排第1个位置和第n-2个位置放上‘#’（0到n-1）。至于为啥子，拿笔画一下就明白了。 C. 阅读全文