Is It A Tree? Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 16702    Accepted Submission(s): 3761 Problem Description A tree is a well-known data structure that is either empty (null, void, n…

Is It A Tree? Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 26002   Accepted: 8879 Description A tree is a well-known data structure that is either empty (null, void, nothing) or is a set of one or more nodes connected by directed edge…

Petya loves lucky numbers. We all know that lucky numbers are the positive integers whose decimal representations contain only the lucky digits 4 and 7. For example, numbers 47, 744, 4 are lucky and 5, 17, 467 are not. One day Petya encountered a tre…

tree 把每条边权是1的边断开,发现每个点离他最近的点个数就是他所在的连通块大小. 开一个并查集,每次读到边权是0的边就合并.最后Ans​i​​=size[findset(i)],size表示每个并查集根的size Ans_i=size[findset(i)],sizeAns​i​​=size[findset(i)],size表示每个并查集根的sizesize. #include<cstdio> #include<cstring> #include<algorithm>…

题目链接:http://acm.swust.edu.cn/problem/856/ Time limit(ms): 1000 Memory limit(kb): 10000 Description There are N trees in a forest. At first, each tree contains only one node as its root. And each node is marked with a number. You're asked to do the fo…

D. Fix a Tree time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output A tree is an undirected connected graph without cycles. Let's consider a rooted undirected tree with n vertices, numbered 1 th…

Is It A Tree? Time Limit:1000MS     Memory Limit:10000KB     64bit IO Format:%I64d & %I64u Submit Status Description A tree is a well-known data structure that is either empty (null, void, nothing) or is a set of one or more nodes connected by direct…

tree Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 986    Accepted Submission(s): 452题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=5606 Problem Description There is a tree(the tree is a conne…

题目链接 dalao们怎么都写的线段树合并啊.. dsu跑的好慢. \(Description\) 给定一棵\(n(n\leq 10^5)\)个点的树. 定义\(Tree[L,R]\)表示为了使得\(L\sim R\)号点两两连通,最少需要选择的边的数量. 求\[\sum_{l=1}^n\sum_{r=l}^nTree[l,r]\] \(Solution\) 枚举每条边,计算它的贡献. 那么我们要判断有多少连续区间的点跨过这条边,并不好算,反过来去求在这条边的两侧分别有多少个连续区间. 那么显然…

Is It A Tree? Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 20222    Accepted Submission(s): 456 Problem Description A tree is a well-known data structure that is either empty (null, void, not…

[题目]F. Imbalance Value of a Tree [题意]给定n个点的带点权树,求所有路径极差的和.n,ai<=10^6 [算法]并查集 [题解]先计算最大值的和,按点权从小到大排序,每个点x和相邻的已访问点的点集形成的路径的最大值都是a[x],因为已访问过的点点权较小,然后用并查集并起来.复杂度O(n log n). #include<cstdio> #include<algorithm> using namespace std; ; ]; int n,a[…

题目链接:https://vjudge.net/contest/271361#problem/E 具体思路:运用并查集,每一次连接上一个点,更新他的父亲节点,如果父亲节点相同,则构不成树,因为入读是2,然后再去遍历每一个点的父亲节点,判断一下祖宗节点有几个,只有1个才能构成树,注意0 0也是树... AC代码: #include<iostream> #include<stack> #include<queue> #include<iomanip> #incl…

tree Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 823    Accepted Submission(s): 394 Problem Description There is a tree(the tree is a connected graph which contains n points and n−1 edges),t…

题目链接:http://codeforces.com/contest/699/problem/D D. Fix a Tree time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output A tree is an undirected connected graph without cycles. Let's consider a root…

原题:http://codeforces.com/contest/699/problem/D 题目中所描述的从属关系,可以看作是一个一个块,可以用并查集来维护这个森林.这些从属关系中会有两种环,第一种是一个点从自身出发到自己,这说明该点是一棵子树的根:第二种是从一点出发到另外一个点.这两种情况在并查集合并的时候都会失败,因为合并时他们都已经属于一个子树,我们现在需要做的就是将这些子树合并,这时我们要优先对生成第二种环的子树进行合并,因为这些从属关系一定是需要修改的,第一种情况有一个点可以不需要修…

POJ终于修好啦 题意 和UVA1205是同一题,在洛谷上是紫题 有一棵树,需要给其所有节点染色,每个点染色所需的时间是一样的都是11.给每个点染色,还有一个开销“当前时间×ci×ci”,cici是每个节点的一个权值.(当前时间是染完这个节点的时间)  染色还有另一个约束条件,要染一个点必须要先染好其父节点,所以第一个染的点是根节点.  求最小开销. 思路 这道题显然对于 每一个可选的子节点选最重的 的贪心思路是错误的 就有点类似动态规划了 不过不DP也是可以贪心出来的.但是这个策略比较麻烦.大…

题目描述 有一棵\(n\)个点的树,最开始所有边都是蓝边.每次你可以选择一条全是蓝边的路径,删掉其中一条,再把这两个端点之间连一条红边.再给你一棵树,这棵树的所有边都是红边,问你最终能不能把原来的树变成这棵新树. \(n\leq 100000\) 题解 考虑最后一条加的边,那么当前也有一条相同的蓝边.也就是说,如果把这两棵树合在一起,这两个点之间会有两条边.然后可以把这两个点缩成一个点. 所以我们每次选择之间有两条边的一对点,把这两个点合在一起.可以直接遍历度数较小的那个点\(x\)相邻的边,把…

https://icpcarchive.ecs.baylor.edu/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=4922 题意是给定一颗森林,然后每次都可以删除一条边,或者询问某两个点是否连通. 如果顺着做是不行的.因为并查集路径压缩了,是删不了边的,(据说不路径压缩能AC,) 所以考虑逆向操作.首先不能把已经删除了的边加进去森林里面,先处理出最终状态,然后倒着模拟,就能把删边操作等价于变…

题目大意:给你一棵树,每个点有点权a_{i},求$\sum _{i=1}^{n} \sum _{j=i}^{n} f(i,j)$,$f(i,j)$表示i,j,路径上的点的最大权值-最小权值 正解的思路好神啊 正解: 首先,原式可以拆成$\sum _{i=1}^{n} \sum _{j=i}^{n} max(i,j) \; - \; \sum _{i=1}^{n} \sum _{j=i}^{n} min(i,j)$ max的求法和min类似,这里只讨论min的求法 把点按照从大到小排序,依次加入树…

Is It A Tree? Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 24237   Accepted: 8311 Description A tree is a well-known data structure that is either empty (null, void, nothing) or is a set of one or more nodes connected by directed edge…

Description A tree is a well-known data structure that is either empty (null, void, nothing) or is a set of one or more nodes connected by directed edges between nodes satisfying the following properties. There is exactly one node, called the root, t…

Cutting Tree 题目连接: https://icpcarchive.ecs.baylor.edu/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=4922 Description Tree in graph theory refers to any connected graph (of nodes and edges) which has no simple cycle, while…

A tree is a well-known data structure that is either empty (null, void, nothing) or is a set of one or more nodes connected by directed edges between nodes satisfying the following properties. There is exactly one node, called the root, to which no d…

题意 (n<=50000) 题解 #include<iostream> #include<cstring> #include<cstdio> #include<cmath> #include<algorithm> using namespace std; ; long long cnt,head[N]; ]; long long fa[N]; long long n,a[N],b[N],book[N],ans; struct edge{ l…

参考网址:http://blog.sina.com.cn/s/blog_6827ac4a0100nyjy.html 解题思路: 由于这里出现的数字不一定连续的数字都会出现,所以设一个mark来标记数字是否出现过.每次输入一对数字的关系则进行查找根结点的函数,即: if(aa==bb) { flag=1; } 如果能查找到根结点就证明二者已经是相通的,再输入二者的关系就变成有多条相通的路径了.如果不能查找到根结点则继续标记他们的关系.到一个数据输入结束后,再进行判断,是否输入的关系每个数字之间都有…

Is It A Tree? 题目链接:http://poj.org/problem?id=1308 Description: A tree is a well-known data structure that is either empty (null, void, nothing) or is a set of one or more nodes connected by directed edges between nodes satisfying the following proper…

Is It A Tree? Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 28838   Accepted: 9843 ->  Link  poj  <- ->  Link  hdu<- ->  Link  NYoj <- 这三个题题目都是一样的,我先做的NYOJ上的,以-1.-1结尾,然后跑到HDu上交一遍跪了,改成同时小于0就A了, 又到POJ上交一遍又跪了,改成-1.-1结尾又A了: 题意…

http://poj.org/problem?id=1308 Description A tree is a well-known data structure that is either empty (null, void, nothing) or is a set of one or more nodes connected by directed edges between nodes satisfying the following properties.There is exactl…

[注意事项] 为了体现增强版,题目限制和数据范围有所增强: 时间限制:1.5s 内存限制:128MB 对于15% 的数据,1<=N,Q<=1000. 对于35% 的数据,1<=N,Q<=10000. 对于50% 的数据,1<=N,Q<=100000,且数据均为官方数据. 对于100% 的数据,1<=N,Q<=1000000. 请注意常数因子对于程序运行的影响. 并查集很简单,并查集就是倒序处理,表示删除一个点的标记,删除后不会再加回来,删完后,合并当前点与其…

[BZOJ2959]长跑(Link-Cut Tree,并查集) 题面 BZOJ 题解 如果保证不出现环的话 妥妥的\(LCT\)傻逼题 现在可能会出现环 环有什么影响? 那就可以沿着环把所有点全部走一遍吧 所以,相当于把环看成一个点来搞一搞 所以,维护一个并查集 记录一下每个点被缩成了哪个点 然后再用\(LCT\)维护缩点后的树就行啦 #include<iostream> #include<cstdio> #include<cstdlib> #include<cs…