题目链接 问题转化 \[a_i+a_j+(i-j)^2=a_i+i^2+a_j+j^2-2ij\] 令 \(b_i=a_i+i^2\) , 问题化为: 求 \[\max \{b_i+b_j-2ij\}, \ (1 \le i, j \le n, i \ne j).\] 固定 \(i\) , 不妨设 \(j<i\) , 定义函数 \[ \begin{equation} F_i(j) = b_j-2ij,\ (1 \le j< i) \end{equation} \] 问题化成: 求 \[ \be…

Problem F Funny Car Racing There is a funny car racing in a city with n junctions and m directed roads. The funny part is: each road is open and closed periodically. Each road is associate with two integers (a, b), that means the road will be open fo…

传送门:http://acm.hdu.edu.cn/showproblem.php?pid=6324 Problem F. Grab The Tree Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 524288/524288 K (Java/Others)Total Submission(s): 1234    Accepted Submission(s): 779 Problem Description Little Q and…

题面: Problem F. Teleportation Input file: standard input Output file: standard output Time limit: 15 second Memory limit: 1024 megabytes   One of the farming chores Farmer John dislikes the most is hauling around lots of cow manure. In order to streamli…

题目链接:https://cn.vjudge.net/contest/245468#problem/F 大意:给你插座和电器的对应关系,有多个电器对应一个插座的情况,但是一个插座只能供一个电器使用,现在有一个转换头,能够将一个插座改成三个插头,问你最多能匹配多少个电器. 思路: HK(洪凯)的思路.先按照没有转换头的思路跑一下匈牙利算法.然后,遍历有多个电器对应一个插座的这种情况,再"加"上两个插座,不过加上的这两个插座,对应关系和你当前正在遍历的这个插座与灯泡的对应关系相同,然后再看…

Problem F. Judging Time Prediction 题目连接: http://www.codeforces.com/gym/100253 Description It is not easy to predict. Do you know that the modern weather prediction is marginally better than to use the previous day weather as a prediction for the next…

Problem F. Finance 题目连接: http://codeforces.com/gym/100714 Description The Big Boss Company (BBC) principal is going to prepare a vacation schedule for the next year. Each employee of BBC gets a four-week vacation each year. A vacation can be divided…

6324.Problem F. Grab The Tree 题目看着好难,但是题解说的很简单,写出来也很简单.能想出来就是简单的,想不出来就难(讲道理,就算是1+1的题目,看不出来就是难的啊). 和后面的东西一点关系都没有... 官方题解: 设sum为所有点权的异或和,A为先手得分,B为后手得分. 若sum=0,则A=B,故无论如何都是平局. 否则考虑sum二进制下最高的1所在那位,一定有奇数个点那一位为1.若先手拿走任意一个那一位为1的点,则B该位为0,故先手必胜. 时间复杂度O(n). 代码…

Weekly Contest 86 A:840. 矩阵中的幻方 3 x 3 的幻方是一个填充有从 1 到 9 的不同数字的 3 x 3 矩阵,其中每行,每列以及两条对角线上的各数之和都相等. 给定一个由整数组成的 N × N 矩阵,其中有多少个 3 × 3 的 “幻方” 子矩阵?(每个子矩阵都是连续的). 直接模拟即可,本来是签到题,由于粗心,浪费了时间. class Solution { public: int numMagicSquaresInside(vector<vector<int&…

1. 551. Student Attendance Record I 2. 552. Student Attendance Record II hihocode原题,https://hihocoder.com/contest/offers10/problems 直接粘贴代码. 其实这个第二题的问题挺多的,这里还是写一下分析过程. 我刚开始做的时候,考虑也是计数dp,一维记录a的个数,一维记录末尾l的个数,然后考虑转移,后来好像是因为转移情况复杂,简化为不考虑a的个数,因为a的个数只有1个,所以…