P3354-[IOI2005]Riv 河流 题目: 题目描述: 几乎整个 Byteland 王国都被森林和河流所覆盖。小点的河汇聚到一起，形成了稍大点的河。就这样，所有的河水都汇聚并流进了一条大河，最

CF980D-Perfect Groups 题目: 题目描述: SaMer has written the greatest test case of all time for one of his problems. For a given array of integers, the problem asks to find the minimum number of groups the array can be divided into, such that the product of any pair of integers in the same group is a perfect square. Each integer must be in exactly

CF1285E-Delete a Segment 题目: 题目描述: There are $ n $ segments on a $ Ox $ axis $ [l_1, r_1] $ , $ [l_2, r_2] $ , …, $ [l_n, r_n] $ . Segment $ [l, r] $ covers all points from $ l $ to $ r $ inclusive, so all $ x $ such that $ l \le x \le r $

CF1304F2-Animal Observation (hard version) 题目: 题目描述: The only difference between easy and hard versions is the constraint on $ k $ . Gildong loves observing animals, so he bought two cameras to take videos of wild animals in a forest. The color of one camera is red, and the other one’s color is blue. Gildong is going to take videos for $ n $

CF1384B2-Koa and the Beach (Hard Version) 题目: 题目描述: The only difference between easy and hard versions is on constraints. In this version constraints are higher. You can make hacks only if all versions of the problem are solved. Koa the Koala is at the beach! The beach consists (from left to right) of a shore, $ n+1 $ meters of sea and an island

CF1399F-Yet Another Segments Subset 题目: 题目描述: You are given $ n $ segments on a coordinate axis $ OX $ . The $ i $ -th segment has borders $ [l_i; r_i] $ . All points $ x $ , for which $ l_i \le x \le r_i $ holds, belong to the $ i $ -th segment. Your task is to choose the