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 perfr…

题目链接 给一棵树, 每条边有权值, 两种操作, 一种是将一条边的权值改变, 一种是询问u到v路径上最大的边的权值. 树链剖分模板. #include <iostream> #include <vector> #include <cstdio> #include <cstring> #include <algorithm> #include <cmath> #include <map> #include <set&g…

思路 注意本题只能用C,不能用C++ 其他的都和上一题一样 代码 #include <stdio.h> #include <string.h> #define MAXN 10010 int dfs_clock,dep[MAXN*2],heason[MAXN*2],id[MAXN*2],sz[MAXN*2],top[MAXN*2],fa[MAXN*2],w_p[MAXN*2],v[MAXN*2],fir[MAXN*2],nxt[MAXN*2],w[MAXN*2],val[MAXN*2…

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:…

QTREE - Query on a tree 题目链接:http://www.spoj.com/problems/QTREE/ 参考博客:http://blog.sina.com.cn/s/blog_7a1746820100wp67.html 树链剖分入门题 代码如下(附注解): #include <cstdio> #include <cstring> #include <iostream> #define lson (x<<1) #define rson…

题目 SP375 QTREE - Query on a tree 解析 也就是个蓝题,因为比较长 树剖裸题(基本上),单点修改,链上查询. 顺便来说一下链上操作时如何将边上的操作转化为点上的操作: 可以看到这个题然我们对边进行操作,我们的树剖是对节点进行操作的,所以我们考虑把边权变为点权. 发现我们节点的点权是连向它的边的边权,所以我们要操作边权的话,我们操作的实际上是其连向点的点权, 假设我们要修改1-4之间的这两条边 我们修改的实际上就是这2,4两个点 我们节点的点权为其父节点连向它的边的边…

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…

[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]…

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&…

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…