思考题 from Maths homework again... 数学小题两道 Problem A You are given a bipartite graph G, find a proper coloring of the complement of G that uses minimum colors. |G|\leq 100 Problem B Given integer N. Find any n\geq N such that n+\varphi(n) is ……

呃呃，笔者最大流水平真是哈哈了，请见本题： 104871C 一眼网络流，怎么构图？ Hint:有费用的网络但是不是最小费用流？那就考虑一下最小割吧！ 一个蛋糕可以考虑成：选择蛋糕->选择工具。一个蛋糕被创造需要：选择蛋糕、选择所有工具。「所有」二字让我们考虑最小割！……

题目：给出一个圆和两点，求这两点间最短路线的距离，要求路线经过圆内部或边上的任意一点。 链接：104871G 如果两个点有一个在圆内（上）就好了…… 如果两个都在圆外，设经过的圆上一点有仰角\alpha，那么注意到答案关于\alpha一定只有一个极小值。就可以三分了！ 难……

欢迎来到YZHT系列，这个系列我将分享我遇到的OI好题。 第一题 笔者最近正在学习数学图论，但是在OI中正巧碰到了这样一道从来没见过的最大流题。虽然难度不大，但是思路比较新： Problem B of 2023-2024 ICPC Southwestern European Regional Contest (SWERC 2023) 顺……

Solved! Difficulty: Div2C :O 竟然有60期了！！ 本期题目来源于Group Theory作业，，，难度不高 Congratulations on the 60th entry!! This problem is from my Group Theory homework (not very hard). Z(Sym(n))=ONE In the world of MATHS, a permutation i……

思考题 aimed for inexperienced participants? Silenced! Ookami and her teammates are taking an English class. The team has n people(animals?) in total. Initially, each person can raise his/her hand and speak freely. However, once a student has raise……

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,……

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……