题目大意 有一张$n$个结点,$m$条混合边的图($1 \leq n \leq 200$,$1 \leq m \leq 1000$),求这张图是否存在欧拉回路. 题解 因为有混合边,所以我们要先给无向边随机定向,然后再调整方向. 随机定向之后,我们就得到一张有向图. 我们记录每个结点的入度$ind[i]$和出度$outd[i]$,根据欧拉路的性质可以得到,当$ind[i] + outd[i]$为奇数时,一定不存在欧拉路. 对于建边过程,因为原有的有向边不能变向,所以我们可以忽略,只需要将读入的无…

太神了,专门写一篇题解 qwq 简要题意:给你 \(R\) 个红球和 \(B\) 个蓝球,你要把它们放到 \(K\) 个箱子里,要求没有两个箱子完全相同(即两种球个数就相同),求 \(K\) 的最大值. 设第 \(i\) 个箱子中有 \(x_i\) 个红球,\(y_i\) 个蓝球,就变成了找平面上一个大小最大的点集 \((x_i,y_i)\),使 \(\sum x_i =R, \sum y_i=B\).进一步,由于可以直接将 \(x\) 最大的点 \(x\) 坐标变大,\(y\) 同理,因此只需…

http://poj.org/problem?id=2135 题目大意: 从1到n再回来,每条边只能走一次,问最短路. —————————————————— 如果不告诉我是费用流打死不会想这个…… 我们把问题简化为1到n跑两遍,然后每条边容量为1,费用为长度. 然后建一个s和t,s到1容量为2,n到t容量为2. 跑费用流. (注意,本题是双向边-!) #include<cstdio> #include<iostream> #include<queue> #include…

http://www.spoj.com/problems/FTOUR2/en/ 题目大意:给一棵黑白染色的树,求边权和最大且经过黑点不超过K的路径. ———————————————————— 前排膜拜hzwer,借(抄)鉴(袭)了神犇的代码与思路,要看简洁的思路的话:http://hzwer.com/5984.html 然而……就算是抄了代码,还是没懂这题怎么做怎么办? 别着急,这道神神神题慢慢来. —————————————————————— 首先判断我们要放什么板子,很显然我们想到的是和树有…

以下代码为了阅读方便,省去以下头文件: #include <iostream> #include <stdio.h> #include <math.h> #include <string.h> #include <time.h> #include <stdlib.h> #include <string> #include <bitset> #include <vector> #include <…

http://www.spoj.com/problems/FTOUR2/ 先前看了一会题解就自己yy出来了...对拍过后交tle.................. 自己造了下大数据........tle......................... what? 首先来看经过当前点的路径: 设g[x,i]表示第x个孩子能得到的路径上黑点最多有i个(注意是最多)的最大长度,因为遍历的节点最坏为n个(第一层),因此在每一层都是$O(n)$的,可以承受. 考虑转移答案 $$ans[x]=max\{…

Description When FJ's friends visit him on the farm, he likes to show them around. His farm comprises N (1 <= N <= 1000) fields numbered 1..N, the first of which contains his house and the Nth of which contains the big barn. A total M (1 <= M <…

Sightseeing tour Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 8628   Accepted: 3636 Description The city executive board in Lund wants to construct a sightseeing tour by bus in Lund, so that tourists can see every corner of the beauti…

这个专栏开始介绍一些<ACM国际大学生程序设计竞赛题解>上的竞赛题目,读者可以配合zju/poj/uva的在线测评系统提交代码(今天zoj貌似崩了). 其实看书名也能看出来这本书的思路,就是一本题解书,简单暴力的通过题目的堆叠来提升解决编程问题的能力. 那么下面开始探索吧. poj1037: Description Background For years, computer scientists have been trying to find efficient solutions to…

A: Decimal Time Limit: 1 Sec   Memory Limit: 128 MB Submit: 99   Solved: 10 [ Submit][ Status][ Web Board] Description 任意一个分数都是有理数,对于任意一个有限小数,我们都可以表示成一个无限循环小数的形式(在其末尾添加0),对于任意一个无限循环小数都可以转化成一个分数.现在你的任务就是将任意一个无限循环小数转化成既约分数形式.所谓既约分数表示,分子和分母的最大公约数是1. Inp…

Description When FJ's friends visit him on the farm, he likes to show them around. His farm comprises N (1 <= N <= 1000) fields numbered 1..N, the first of which contains his house and the Nth of which contains the big barn. A total M (1 <= M <…

Codeforces Round #545 Div1 题解 来写题解啦QwQ 本来想上红的,结果没做出D.... A. Skyscrapers CF1137A 题意 给定一个\(n*m\)的网格,每个格子里都有一个数,对于任意一行和任意一列,要求把这\(n+m-1\)个数重新用正整数编号,并且对于这一行,数与数之间的大小关系不变,对于这一列同理.求出任意一行和任意一列编号使用的最大编号的最小值. 题解 读题读半天... 看懂了题目就不难了. 对于每一行和每一列先分别离散,记录每个位置在离散后的值…

BC都被hack的人生,痛苦. 下面是题解的表演时间: A. QAQ "QAQ" is a word to denote an expression of crying. Imagine "Q" as eyes with tears and "A" as a mouth. Now Diamond has given Bort a string consisting of only uppercase English letters of leng…

描述 The city executive board in Lund wants to construct a sightseeing tour by bus in Lund, so that tourists can see every corner of the beautiful city. They want to construct the tour so that every street in the city is visited exactly once. The bus s…

描述 When FJ's friends visit him on the farm, he likes to show them around. His farm comprises N (1 <= N <= 1000) fields numbered 1..N, the first of which contains his house and the Nth of which contains the big barn. A total M (1 <= M <= 10000)…

Description When FJ's friends visit him on the farm, he likes to show them around. His farm comprises N (1 <= N <= 1000) fields numbered 1..N, the first of which contains his house and the Nth of which contains the big barn. A total M (1 <= M <…

嗯,这是我上一篇文章说的那本宝典的第二题,我只想说,真TM是本宝典……做的我又痛苦又激动……(我感觉ACM的日常尽在这张表情中了) 题目链接:http://poj.org/problem?id=1637 Time Limit: 1000MS Memory Limit: 10000K Description The city executive board in Lund wants to construct a sightseeing tour by bus in Lund, so that t…

刷题备忘录,for bug-free 招行面试题--求无序数组最长连续序列的长度,这里连续指的是值连续--间隔为1,并不是数值的位置连续 问题: 给出一个未排序的整数数组,找出最长的连续元素序列的长度. 如: 给出[100, 4, 200, 1, 3, 2], 最长的连续元素序列是[1, 2, 3, 4].返回它的长度:4. 你的算法必须有O(n)的时间复杂度 . 解法: 初始思路 要找连续的元素,第一反应一般是先把数组排序.但悲剧的是题目中明确要求了O(n)的时间复杂度,要做一次排序,是不能达…

Betsy's TourDon Piele A square township has been divided up into N2 square plots (1 <= N <= 7). The Farm is located in the upper left plot and the Market is located in the lower left plot. Betsy takes her tour of the township going from Farm to Mark…

Canada Tour You have won a contest sponsored by an airline. The prize is a ticket to travel around Canada, beginning in the most western point served by this airline, then traveling only from west to east until you reach the most eastern point served…

B. World Tour 题目连接: http://www.codeforces.com/contest/666/problem/B Description A famous sculptor Cicasso goes to a world tour! Well, it is not actually a world-wide. But not everyone should have the opportunity to see works of sculptor, shouldn't he…

POI2012题解 这次的完整的\(17\)道题哟. [BZOJ2788][Poi2012]Festival 很显然可以差分约束建图.这里问的是变量最多有多少种不同的取值. 我们知道,在同一个强连通分量中的变量的相对大小是限制死了的,即这个强连通分量中的最大值减去最小值不为\(\inf\),而这个区间中的所有数一定都可以被取到(因为这里的边权只有\(0,\pm1\)嘛),所以一个强连通分量对答案的贡献是这个强连通分量中的最长路\(+1\).对于不在同一个强连通分量中的变量,其相对大小不受限制,取…

题意懒得写了 LOJ Day 1 T1 鱼 个人做法比较猎奇,如果有哪位大佬会证明能分享一下的话感激不尽. 题解:枚举鱼尾和鱼身的交点D,将所有其他点按照到D的距离排序,距离相同的分一组. 感性的理解,对于每个点D,暴力枚举距离相等的点对(B,C).这样总的数量不会很多.感觉仍然是\(O(n^2)\)级别的. 那么我们对枚举的D,将所有的点对的中垂射线和点按照极角排序,扫一圈就能得到答案了.鱼尾的部分也是利用扫描线,用叉积判断可能会有问题(转过了180度),那么我们可以将其倍长,用极角的值来判即…

洛谷题目链接:[USACO5.4]周游加拿大Canada Tour 题目描述 你赢得了一场航空公司举办的比赛,奖品是一张加拿大环游机票.旅行在这家航空公司开放的最西边的城市开始,然后一直自西向东旅行,直到你到达最东边的城市,再由东向西返回,直到你回到开始的城市.除了旅行开始的城市之外,每个城市只能访问一次,因为开始的城市必定要被访问两次(在旅行的开始和结束). 当然不允许使用其他公司的航线或者用其他的交通工具. 给出这个航空公司开放的城市的列表,和两两城市之间的直达航线列表.找出能够访问尽可能多…

题目链接 A. Sushi for Two 题意 在一个 01 序列中找出长为偶数的连续的一段使得它前一半和后一半内部分别相同,而前一半和后一半不同. \(2\le n\le 100\ 000\) 题解 令共有 \(k\) 段连续的区间,第 \(i\) 段区间的长度设为 \(a_i\),则答案是在求 \(\max_{i=1}^{k-1}\min(a_i,a_{i+1})\).我因为没好好判 \(\min\) 而轻松地丢掉了 WA on pretest 4 的50分. 代码 标签 枚举 B. Ci…

Sightseeing tour Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 10581   Accepted: 4466 题目链接:http://poj.org/problem?id=1637 Description: The city executive board in Lund wants to construct a sightseeing tour by bus in Lund, so that touri…

Tour Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 65535/65535 K (Java/Others)Total Submission(s): 4279    Accepted Submission(s): 2041 题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=3488 Description: In the kingdom of Henryy, there are N (…

[BZOJ3060][Poi2012]Tour de Byteotia Description 给定一个n个点m条边的无向图,问最少删掉多少条边能使得编号小于等于k的点都不在环上. Input        第一行三个整数n,m,k:        接下来m行每行两个整数ai,bi,表示ai和bi之间有一条无向边. Output        一个整数,表示最少的删边数量. Sample Input 11 13 5 1 2 1 3 1 5 3 5 2 8 4 11 7 11 6 10 6 9 2…

Cyclic Tour Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/65535 K (Java/Others)Total Submission(s): 1688    Accepted Submission(s): 859 Problem Description There are N cities in our country, and M one-way roads connecting them. Now Li…

题目链接:http://poj.org/problem?id=2135 Farm Tour Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 17672   Accepted: 6851 Description When FJ's friends visit him on the farm, he likes to show them around. His farm comprises N (1 <= N <= 1000…