Description User ainta has a permutation p1, p2, ..., pn. As the New Year is coming, he wants to make his permutation as pretty as possible. Permutation a1, a2, ..., an is prettier than permutation b1, b2, ..., bn, if and only if there exists an inte…

Marriage Match II Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 5469    Accepted Submission(s): 1756 题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=3081 Description: Presumably, you all have k…

http://codeforces.com/contest/691/problem/D D. Swaps in Permutation   You are given a permutation of the numbers 1, 2, ..., n and m pairs of positions (aj, bj). At each step you can choose a pair from the given positions and swap the numbers in that…

题目链接:http://codeforces.com/contest/691/problem/D 题意: 题目给出一段序列,和m条关系,你可以无限次互相交换这m条关系 ,问这条序列字典序最大可以为多少 思路: 并查集维护这m条关系,用个vector存一下当前点所能到达的点,拍下序大的优先,输出的时候输出当前点所能找到的最大的数,已输出的标记下就好了. 实现代码: #include<bits/stdc++.h> using namespace std; ; int f[M],vis[M],a[M…

User ainta has a permutation p1, p2, ..., pn. As the New Year is coming, he wants to make his permutation as pretty as possible. Permutation a1, a2, ..., an is prettier than permutation b1, b2, ..., bn, if and only if there exists an integer k (1 ≤ k…

题目链接:http://poj.org/problem?id=1236 这题本来是个强连通分量板子题的,然而弱很久不写tarjan所以生疏了一下,又看这数据范围觉得缩点这个事情可以用点到点之间的距离来判断不知道群巨兹磁不兹磁……下面弱就给大家搞一发如何用floyd和并查集来缩点……大致的思路就是先floyd跑出所有距离,然后O(n^2)找两两都可达的点,把它们的关系用并查集来维护.接下来O(n)找并查集里的代表元素.这个时候应当特判一下连通块为1的时候.再O(n^2)找出所有单向边,然后更新所有…

题目链接:http://codeforces.com/problemset/problem/400/D 题目大意: 给定n个集合,m步操作,k个种类的细菌, 第二行给出k个数表示连续的xi个数属于i集合. 当某个种类之间两两交换的值都为0可行解,则输出所有种类之间交换的最小值:否则输出No 解题思路:当两点之间的距离为0时并查集到一个集合中,只需保证最终同一种类的细菌都在一个并查集中则是符合条件的可行解,再用FLOYD找最短路即可 #include<cmath> #include<cst…

度度熊保护村庄 Accepts: 13 Submissions: 488 Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Problem Description 哗啦啦村袭击了喵哈哈村! 度度熊为了拯救喵哈哈村,带着自己的伙伴去救援喵哈哈村去了!度度熊与伙伴们很快的就过来占据了喵哈哈村的各个军事要地,牢牢的守住了喵哈哈村. 但是度度熊发现,这是一场旷日持久的战斗,所以度度熊决定要以逸…

对于一个图,如何求出其中的最小环(不包括一元环)? 很显然,对于一个无向图,每一条边都是一个二元环:对于有向图,可以考虑从每一个点出发,用DFS求出它到自己的距离,如果遍历了$N$个点仍未便利到自己,则该点不在环中.但是这样做的复杂度非常感人……如果没有分析错的话最坏应该是$O(n^2 m)$ 可以考虑有一些优化, 对于一个点,如果它在一个环中,那么它在该环上dfs过的点一定在环中.在回溯一个点的过程中,如果搜到环,那么在搜下一个点的时候就不清空他们的标记数组.对于搜不到环的点,它的入度一定为一…

D. Swaps in Permutation 题目连接: http://www.codeforces.com/contest/691/problem/D Description You are given a permutation of the numbers 1, 2, ..., n and m pairs of positions (aj, bj). At each step you can choose a pair from the given positions and swap…

题意:给出n个点,分别属于k个集合,判断每个集合里面的点的距离都为0,为0的话输出yes,并输出任意两个集合之间的最短路 这道题目有两个地方不会处理, 先是n个点,分别属于k个集合,该怎么记录下来这里, 然后就是判断每个集合里面的点的距离是否为1,这里可以用并查集来做,如果在输入点的时候,距离为0,就将这两点合并 最后判断每个点,如果他们同属于一个集合,判断它俩的根是否一样就可以了 最后用floyd求最短路 #include<iostream> #include<cstdio> #…

Communication 题目描述 The Ministry of Communication has an extremely wonderful message system, designed by the President himself. For maximum efficiency, each office in the Ministry can send a message directly to some, but not necessarily all, other off…

Communication 题目链接(点击) 题目描述 The Ministry of Communication has an extremely wonderful message system, designed by the President himself. For maximum efficiency, each office in the Ministry can send a message directly to some, but not necessarily all,…

题目链接:http://codeforces.com/problemset/problem/691/D 给你n个数,各不相同,范围是1到n.然后是m行数a和b,表示下标为a的数和下标为b的数可以交换无数次.问你最后字典序最大的数列是什么. 将下面的a和b用并查集联系起来存到祖节点对应的数组中,然后从大到小排序数组,最后依次按照父节点的数组中的顺序输出. 也可以用dfs的方法解(略麻烦),形成一个环路的就在一个数组中... //并查集 #include <bits/stdc++.h> using…

题目链接: http://codeforces.com/problemset/problem/691/D 题目大意: 给一个1到N的排列,M个操作(1<=N,M<=106),每个操作可以交换X Y位置上的数字,求可以得到的最大字典序的数列. 题目思路: [搜索][并查集] 这题可以用搜索或者并查集写,都能过. 把位置分成若干块,每一块里面的位置都是可以被这一块里另一个位置经过若干次调换的(类似强连通,位置可达). 然后把每一块位置里的 位置按从小到大排序,位置上的值按从大到小排序,依次填入位置…

在很多时候,并查集并不是一个完整的解题方法,而是一种思路. 通过以下题目来体会并查集逆向运用的思想. Description Farmer John and his cows are planning to leave town for a long vacation, and so FJ wants to temporarily close down his farm to save money in the meantime.The farm consists of NN barns con…

链接:Destroying Array C. Destroying Array time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output You are given an array consisting of n non-negative integers a1, a2, ..., an. You are going to destro…

http://poj.org/problem?id=1797 题意:就是从第一个城市运货到第n个城市,最多可以一次运多少货. 输入的意思分别为从哪个城市到哪个城市,以及这条路最多可以运多少货物. 思路:我觉得可以用floyd来做这道题,结果交上去就TLE了,不过时间复杂度为n3TLE看起来也是比较正常,毕竟数字大. 然后我就看到网上有人用并查集来做,不然以前我都没往这方面想过,然后就用并查集来做 用并查集的思路就是,首先,对每组数据按照重量由大到小进行排序.然后查找合并.当Find(n) ==…

A. Broken Clock time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output You are given a broken clock. You know, that it is supposed to show time in 12- or 24-hours HH:MM format. In 12-hours format…

题目描述 in English: Farmer John and his cows are planning to leave town for a long vacation, and so FJ wants to temporarily close down his farm to save money in the meantime. The farm consists of NN barns connected with MM bidirectional paths between so…

时间限制(普通/Java):5000MS/15000MS     内存限制:65536KByte 描述 NKU ACM最近要举行足球赛,作为此次赛事的负责人,Lee要对报名人员进行分队.分队要遵循如下原则: 一个人不能加入多支队伍:不认识的人不能分在同一队:如果a和b认识,b和c认识,那么认为a和c也认识:每支队伍上限8人,下限5人:尽量使队伍满员.由于参赛人数很多,Lee表示无能为力,所以请你帮助Lee编程解决比赛有多少队伍. 输入 第一行输入两个整数,n和m,n(1<=n<=300000)…

C. Destroying Array 题目连接: http://codeforces.com/contest/722/problem/C Description You are given an array consisting of n non-negative integers a1, a2, ..., an. You are going to destroy integers in the array one by one. Thus, you are given the permuta…

find the most comfortable road Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 7519    Accepted Submission(s): 3171 Problem Description XX星有许多城市,城市之间通过一种奇怪的高速公路SARS(Super Air Roam Structure---超级…

题目描述 Farmer John and his cows are planning to leave town for a long vacation, and so FJ wants to temporarily close down his farm to save money in the meantime.The farm consists of NN barns connected with MM bidirectional paths between some pairs of b…

A. Petr and a calendar time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Petr wants to make a calendar for current month. For this purpose he draws a table in which columns correspond to wee…

http://abc049.contest.atcoder.jp/tasks/arc065_b 一开始做这题的时候,就直接蒙逼了,n是2e5,如果真的要算出每一个节点u能否到达任意一个节点i,这不是floyd吗?复杂度要达到n^3,bitset优化也没用了.然后想了想,肯定不是的,如果有很快的方法能判断出一张图的两个节点是否连通,那floyd就没用了.然后想了一节课,发现还是需要判断是否相连啊,不判断就没得玩了. 然后想到了并查集,确实可以很快判断是否相连了.然后我就想那floyd就没啥用了吧.…

C. Destroying Array time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output You are given an array consisting of n non-negative integers a1, a2, ..., an. You are going to destroy integers in the ar…

春训团队赛第四场 ID A B C D E F G H I J K L M AC O O O O O O O O O 补题 ? ? O O 传送门 题目链接(CF Gym102021) 题解链接(pdf) 代码 & 简易题解 [A]:LCA 给定一个格状迷宫,保证任意点均可达,且任意两格点间有且仅有一条简单路径. 给定一组移动序列,求按照这个序列走的累计路程. 按照题意对图预处理,得到一棵树,对于每对询问求 \(\text{LCA}\) 的同时求距离,累加即为答案. 一开始 \(\text{RE…

http://acm.whu.edu.cn/land/problem/detail?problem_id=1542 今天做武大的网赛题,哎,还是不够努力啊,只搞出三个 这个题目一看就是个最短路,但是题目数据量太大,n^2承受不起,而且如果只是个最短路,那题目花这么大力气叙述有些城市可以互相免费干嘛呢 这个是聪哥发现的神奇的细节,题目里说It is guaranteed that there are no more 200 coalitions.暂且把这个称作空域,也就是说最终免费的城市都成了一个…

线段树(区间修改,区间和): #include <cstdio> #include <iostream> #include <cstring> using namespace std; ],n,m; char s; void update(int p,int l,int r,int x,int add) { ; if (l==r) { c[p]+=add; return; } ,l,m,x,add); +,m+,r,x,add); c[p]=c[p<<]+c…