思考题 in mid autumn This is hard version of Ep.58. If you prefer easier problems, please visit this link. LianLi Branches II Wulpit has drawn n nodes(indexed from 1 to n) and n-m edges on paper for homework assignments. They form m rooted trees (a……

Solved! Difficulty: Div2 C 思考题 in mid autumn This is easy version of Ep.59. If you prefer harder problems, please visit this link. LianLi Branches Wulpit has drawn n nodes(indexed from 1 to n) and n-m edges on paper for homework assignment……

Solved! Difficulty: Div2B 1 problem for div3 participants. Beautiful Dice Painting When Epis is bored, she will draw dices. The canvas contains n*n dots. Initially they are all white. You need to paint exactly v dots black so that the final c……

trivial 思考题 I am Banach This is a classic problem by Banach nearly without any change. There are N boys and M girls. Each boy loves a single girl and each girl loves a single boy. Your task is to divide the boys into two groups A_0 and A_1 and t……

Starting from today, we will try to write tutorials and rate difficulties for already solved Orange Boy Can You Solve It Out?(OBCYSIO) problems and separate them from unsolved/unsolvable ones. There's a new category called Solved OBCYSIO and you ca……

思考题 during OI recovery Rubbish Problem Maybe you have heard of the evil problem Hilbert's Hedge Maze and here's another very fun problem! You have n items arranged in rows. Each row contains r items and the items are arranged from left to right,……

概述 本文为XGN（后文称笔者）与其母（后文称母）于令和五年八月六日到十四日的日本国游记，在HHS博客上发表，XGN博客上转录。 「日行紀要」（にこうきよう）？ 在笔者之前，已经有一篇翔实而又生动的游记——日本国游记 笔者不及Z氏的文笔和才华，本文也只是简单概述所……

思考题 with hard-to-write checker and interactor Peripheral Lightup! Note: this is not a traditional problem. Follow the instruction in the statement to help construct your solution Lead-in: The Palace is celebrating a festival with LED lights! Ins……

Have you ever imagined a crossover between Touhou and Spice&Wolf? Now there is! Introduction S&W:MoF is a fangame of Touhou and Spice and Wolf: My year with Holo. In the game, the player roleplays the merchant Lawrence and embarks on a jour……

大家好，笔者是2023届高中毕业生XGN。最近有幸参加了南京大学的2023届强基计划招生，现分享一下经历： 初赛 初赛人很多，在仙林校区进行。笔者报名的专业考察内容是「数理探究」（aka数学+物理）。考试时间1.5h，12道数学，12道物理，选择题，6个选项，满分100.每门学……