Query on a tree Time Limit: 5000ms Memory Limit: 262144KB   This problem will be judged on SPOJ. Original ID: QTREE64-bit integer IO format: %lld      Java class name: Main Prev Submit Status Statistics Discuss Next Font Size: + - Type:   None Graph…

题目链接:http://www.spoj.com/problems/PT07J/ 题意:给出一个有根树,1为根节点,每个节点有权值.若干询问,询问以u为根的子树中权值第K小的节点编号. 思路:DFS一次,记录每个节点在DFS序列中的开始和结束位置.那么以u为节点的子树的所有点都在两个u之间.那么询问就转化成询问区间的第K小值,可以将DFS序列建立划分树解决. #include <iostream>#include <cstdio>#include <string.h>#…

题目链接:http://www.spoj.com/problems/QTREE/en/ QTREE - Query on a tree #tree You are given a tree (an acyclic undirected connected graph) with N nodes, and edges numbered 1, 2, 3...N-1. We will ask you to perfrom some instructions of the following form:…

这道题是树链剖分的裸题,正在学LCT,用LCT写了,发现LCT代码比树链剖分还短点(但我的LCT跑极限数据用的时间大概是kuangbin大神的树链剖分的1.6倍,所以在spoj上是850ms卡过的). 收获: 1.边转换成点(即若存在边(u,v),则新加一个点z代表边,将z连接u和v,z的点权就是(u,v)的边权,非边点的权设为-oo),然后对边权的统计就变成了对点权的统计(这是LCT中处理边信息的通法之一). 2.若要连接两个点u,v,先让它们分别称为根,然后将其中一个的path-parent…

[题目分析] 垃圾vjudge又挂了. 树链剖分裸题. 垃圾spoj,交了好几次,基本没改动却过了. [代码](自带常数,是别人的2倍左右) #include <cstdio> #include <cstring> #include <iostream> #include <algorithm> using namespace std; #define maxn 20005 int T,n,fr[maxn],h[maxn],to[maxn],ne[maxn]…

第一次写树剖~ #include<iostream> #include<cstring> #include<cstdio> #define L(u) u<<1 #define R(u) u<<1|1 using namespace std; ; ],next1[MAX*],tov[MAX*],val[MAX*],tot,n; int fa[MAX],w[MAX],son[MAX],depth[MAX],tot2,size[MAX]; ],tree…

题意:给一颗n个点的树,有两种操作CHANGE i ti : 把第i条边的权变为tiQUERY a b : 问点a 到 点b 之间的边的最大权 思路:树剖处理边权.由于是边,所以只需要把边权处理到子节点上即可(查询的时候从节点2开始查询,或者把0处理成负无穷) 具体见代码: + ; ; //线段树部分 int set_value, qL, qR; int maxv[maxnode]; void update(int o, int L, int R) { if (qL <= L &&…

题意:给一棵树,每次更新某条边或者查询u->v路径上的边权最大值. 解法:做过上一题,这题就没太大问题了,以终点的标号作为边的标号,因为dfs只能给点分配位置,而一棵树每条树边的终点只有一个. 询问的时候,在从u找到v的过程中顺便查询到此为止的最大值即可. 代码: #include <iostream> #include <cstdio> #include <cstring> #include <cstdlib> #include <cmath&…

Query on a tree again! 给出一棵树,树节点的颜色初始时为白色,有两种操作: 0.把节点x的颜色置反(黑变白,白变黑). 1.询问节点1到节点x的路径上第一个黑色节点的编号. 分析: 先树链剖分,线段树节点维护深度最浅的节点编号. 注意到,如果以节点1为树根时,显然每条重链在一个区间,并且区间的左端会出现在深度浅的地方.所以每次查找时发现左区间有的话,直接更新答案. 9929151 2013-08-28 10:45:55 Query on a tree again! 100…

  Query on a tree Time Limit: 851MS   Memory Limit: 1572864KB   64bit IO Format: %lld & %llu Submit Status Description You are given a tree (an acyclic undirected connected graph) with N nodes, and edges numbered 1, 2, 3...N-1. We will ask you to per…

QTREE - Query on a tree #number-theory You are given a tree (an acyclic undirected connected graph) with N nodes, and edges numbered 1, 2, 3...N-1. We will ask you to perfrom some instructions of the following form: CHANGE i ti : change the cost of t…

传送门:Problem QTREE https://www.cnblogs.com/violet-acmer/p/9711441.html 题解: 树链剖分的模板题,看代码比看文字解析理解来的快~~~~~~~ AC代码献上: #include<iostream> #include<cstdio> #include<cmath> #include<cstring> using namespace std; #define ls(x) ((x)<<1…

https://vjudge.net/problem/SPOJ-QTREE 题意: 给出一棵树,树上的每一条边都有权值,现在有查询和更改操作,如果是查询,则要输出u和v之间的最大权值. 思路: 树链剖分的模板题. 树链剖分简单来说,就是把树分成多条链,然后再将这些链映射到数据结构上处理(线段树,树状数组等等). 具体的话可以看看这个http://blog.sina.com.cn/s/blog_6974c8b20100zc61.html #include<iostream> #include&l…

375. Query on a tree Problem code: QTREE You are given a tree (an acyclic undirected connected graph) with N nodes, and edges numbered 1, 2, 3...N-1. We will ask you to perfrom some instructions of the following form: CHANGE i ti : change the cost of…

You are given a tree (an acyclic undirected connected graph) with N nodes, and edges numbered 1, 2, 3...N-1. We will ask you to perfrom some instructions of the following form: CHANGE i ti : change the cost of the i-th edge to tior QUERY a b : ask fo…

PT07J - Query on a tree III #tree You are given a node-labeled rooted tree with n nodes. Define the query (x, k): Find the node whose label is k-th largest in the subtree of the node x. Assume no two nodes have the same labels. Input The first line c…

Query on a tree II You are given a tree (an undirected acyclic connected graph) with N nodes, and edges numbered 1, 2, 3...N-1. Each edge has an integer value assigned to it, representing its length. We will ask you to perfrom some instructions of th…

Query on a tree You are given a tree (an acyclic undirected connected graph) with N nodes, and edges numbered 1, 2, 3...N-1. We will ask you to perfrom some instructions of the following form: CHANGE i ti : change the cost of the i-th edge to ti or Q…

You are given a tree (an acyclic undirected connected graph) with n nodes. The tree nodes are numbered from 1 to n. Each node has a color, white or black. All the nodes are black initially. We will ask you to perform some instructions of the followin…

You are given a tree (an acyclic undirected connected graph) with N nodes. The tree nodes are numbered from 1 to N. We define dist(a, b) as the number of edges on the path from node a to node b. Each node has a color, white or black. All the nodes ar…

You are given a tree (an acyclic undirected connected graph) with N nodes. The tree nodes are numbered from 1 to N. In the start, the color of any node in the tree is white. We will ask you to perfrom some instructions of the following form: 0 i : ch…

[题目分析] QTREE4的弱化版本 建立出分治树,每个节点的堆表示到改点的最近白点距离. 然后分治树上一直向上,取min即可. 正确性显然,不用担心出现在同一子树的情况(不会是最优解),请自行脑补. 然后弱渣我写了1.5h [代码] #include <queue> #include <cstdio> #include <cstring> #include <iostream> #include <algorithm> using namesp…

[题目分析] QTREE2,一看是倍增算法,太懒了,不写了.(￣_,￣ ) QTREE3,树链剖分可以做,发现链上的问题LCT也很好做. 要是子树问题貌似可以DFS序. 然后就成LCT模板题了. 考前背板模式开启了. [代码] #include <cstdio> #include <cstring> #include <iostream> #include <algorithm> using namespace std; #define maxn 10000…

题目大意:给你一棵树,有两个操作1.修改一条边的值,2.询问从x到y路径上边的最大值 思路:如果树退化成一条链的话线段树就很明显了,然后这题就是套了个树连剖分,调了很久终于调出来第一个模板了 #include<iostream> #include<cstdio> #include<cstring> #define maxn 100009 using namespace std; ],point[maxn],son[maxn],size_k[maxn],id[maxn],…

\(\\\) Description 其实这题才是正版的 Qtree3...... 给定 \(n\) 个点,以 \(1\) 号节点为根的树,点有点权. \(m\) 次询问 以 \(x\) 为根的子树内,点权第 \(k\) 小的 节点编号 是多少. 有多组测试数据,每组数据以 \(DONE\) 结尾. \(n,m\le 10^5\) \(\\\) Solution 注意到一棵树的子树 \(DFS\) 序是连续的. 一遍 \(DFS\) 确定 \(DFS\) 序以及各个点的子树大小. 在 \(DFS…

\(\\\) Description 给定 \(n\) 个点的树,边按输入顺序编号为\(1,2,...n-1\) . 现要求按顺序执行以下操作(共 \(m\) 次): \(CHANGE\ i\ t_i\) 将第 \(i\) 条边权值改为 \(t_i\) \(QUERY\ a\ b\) 询问从 \(a\) 点到 \(b\) 点路径上的最大边权 有多组测试数据,每组数据以 \(DONE\) 结尾 \(n,m\le 10^5\) \(\\\) Solution 重链剖分,线段树维护. 把边权记录在深度…

spoj题面 Time limit 433 ms //spoj的时限都那么奇怪 Memory limit 1572864 kB //1.5个G,疯了 Code length Limit 15000 B OS Linux Language limit All except: ERL JS-RHINO NODEJS PERL6 VB.NET Source Special thanks to Ivan Krasilnikov for his alternative solution Author Th…

题目链接 引用到的大佬博客 代码来自:http://blog.csdn.net/jinglinxiao/article/details/72940746 具体算法讲解来自:http://blog.sina.com.cn/s/blog_7a1746820100wp67.html 参考博客: http://www.cnblogs.com/barrier/p/6067964.html http://www.cnblogs.com/sagitta/p/5660749.html “在一棵树上进行路径的修改…

树链剖分,线段树维护~ #include <cstdio> #include <cstring> #include <iostream> #include <algorithm> #include <vector> using namespace std; ; struct Edge { int to,next; }edge[MAXN*]; int head[MAXN],tot; int top[MAXN];//top[v]表示v所在的重链的顶端…

Description 给出一个树,每条边有边权,支持两种操作,询问 \(u,v\) 路径上边权最大值,修改第 \(i\) 条边的边权,\(n\leqslant 10^4,T\leqslant 10\) Sol 树链剖分. 基于边的树链剖分,对于一个点,可能有许多儿子,但是它只能有一个父亲,给它编号表示它到它父亲的边,只需要修改查询的是最后一步就可以了. Code #include<cstdio> #include<vector> #include<iostream>…