PKU SC 2019 Diary Day 2 如果您是大佬，请不要阅读 Morning 恰早饭…… 重点是早上的大师讲坛。讲师是John Hopcroft from Cornell University.讲了一些杂谈，不过都是英语（汗）。凭借着我的高超英语水平猜测能力，大概讲了如下内容： - 一个D刺螈的球体的体积当D趋于∞……

PKU SC 2019 Diary Day 1 备注：如果您是大佬，请不要往下阅读 Morning 在Hotel吃的早餐，虽然很想睡觉，但是早饭就糊过去。早饭的时候有一对日本金松夫妇和一个翻译……翻译一直在说：“それそれ”什么的…… 然后参加了开营仪式，和冬令营的一模一样，嗯，太好了，浪费50……

PKU SC 2019 Day 0 又是一个学期来PKU……这次来到了真正的北京上次是假北京真广州 Nanjing ~ On the way ~ 走的时候就在堵车……早上8点的火车，7点出发，途中经过宁海中学和鼓楼实验小学，然后，你们也知道的。对，路堵死了……结果堵了半天。你美死了 Nanjing ~ On the t……

思考题 for no one Tour You are given a tree of N nodes. Given another integer array A of length M. Little CMJ chooses M sequences of nodes. The i-th of them is X_1,X_2...X_{A_i} and he chooses them so that for each 1\leq i\leq A_i-1,there's an edge……

思考题 for blue boy Roguelike Tree Statement You are given a tree of N nodes. Each node could be 3 status: passable(.), impassable(X), unknown(?). Now we randomly replace each "unknown" to "passable" or "impassable" then we need to find out the exp……

思考题 for nobody Rougelike Game You are given a graph of N*M grids. Each grid can be a wall 'X',a path'.' or unknown '?' One grid is the start point 'S' and one grid is the end point 'E' Now we change the '?' randomly to 'X' or '.' and run shortes……

JSOI 2019 Diary Day 4 又是一场噩梦…… Problem A 一道毒瘤题的样子？读了2遍才把题目读懂……然后发现就不会做了。先去做T2了。 Problem B 我一看，和我出给300iq的神秘题目一样吗？不过要计数，难度瞬间上去了……10分的状压DP还是蛮好写的，然后写了20分的排列组合WA掉……

JSOI 2019 Diary Day 3 第一轮烤考炸掉了我又厚颜无耻充满希望的回来啦！这次比赛是2019/4/28日在熟悉的南航举行。今天是试机日……本来不打算来的，但是试机可以不上HBHB说晚上不上课来试机，于是我就来了。 preInit(); 来得太早，人家还在上课……只能在教室外面等。看……

Rong Kong is a filial boy. There are N pears on the table. Both he and his brother can eat them. They both want to eat as much as they can. Each of them weighs a[i]. It costs a[i] time for a boy to eat a pear weighing a[i] and it gives him a[i] sat……

思考题 for everyone Man on Graph Given a graph of N nodes and M edges. On node i there are A_i men. Then each person moves along 1 edge randomly connected to the node he stands. But if two men walked along the same edge, they'll fight and both die.……