题目链接 http://codeforces.com/blog/entry/43230树上莫队从这里学的,  受益匪浅.. #include <iostream> #include <vector> #include <cstdio> #include <cstring> #include <algorithm> #include <cmath> #include <map> #include <set> #i…

大概学了下树上莫队, 其实就是在欧拉序上跑莫队, 特判lca即可. #include <iostream> #include <algorithm> #include <cstdio> #include <math.h> #include <set> #include <map> #include <queue> #include <string> #include <string.h> #incl…

树上莫队就是把莫队搬到树上-利用欧拉序乱搞.. 子树自然是普通莫队轻松解决了 链上的话 只能用树上莫队了吧.. 考虑多种情况 [X=LCA(X,Y)] [Y=LCA(X,Y)] else void dfs(int u) { sz[u] = 1 ; rev[st[u] = ++ cnt] = u ; for(int i = 0 ; i < G[u].size() ; i ++) { int v = G[u][i] ; if(v == fa[u]) { continue ; } fa[v] = u…

题意: 给出一棵\(n(n \leq 4 \times 10^4)\)个节点的树,每个节点上有个权值,和\(m(m \leq 10^5)\)个询问. 每次询问路径\(u \to v\)上有多少个权值不同的点. 分析: 树分块 首先将树分块,每块的大小为\(\sqrt{n}\)左右. 然后将询问离线处理,按照区间上的莫队算法将询问按块排序. 这里有一道裸的树分块的题目. 树上的路径转移 定义\(S(u,v)\)表示路径\(u \to v\)上的点集,定义\(\bigoplus\)为集合的对称差,类…

树上莫队模板题. 使用欧拉序将树上路径转化为普通区间. 之后莫队维护即可.不要忘记特判LCA #include<iostream> #include<cstdio> #include<cstring> #include<cmath> #include<algorithm> #define N 200005 using namespace std; int read() { ,f=;char ch=getchar(); ;ch=getchar();…

题目分析: 考虑欧拉序,这里的欧拉序与ETT欧拉序的定义相同而与倍增LCA不同.然后不妨对于询问$u$与$v$让$dfsin[u] \leq dfsin[v]$,这样对于u和v不在一条路径上,它们可以改成询问$dfsin[u]$到$dfsin[v]$.否则改成$dfsout[u]$到$dfsin[v]$,并加上LCA上的影响,如果在询问过程中没有加入就加入,否则删除. 代码: #include<bits/stdc++.h> using namespace std; ; ; ; int n,m;…

SPOJ10707 COT2 Count on a tree II Solution 我会强制在线版本! Solution戳这里 代码实现 #include<stdio.h> #include<stdlib.h> #include<string.h> #include<math.h> #include<algorithm> #include<queue> #include<set> #include<map>…

COT2 - Count on a tree II #tree You are given a tree with N nodes. The tree nodes are numbered from 1 to N. Each node has an integer weight. We will ask you to perform the following operation: u v : ask for how many different integers that represent…

COT2 - Count on a tree II You are given a tree with N nodes. The tree nodes are numbered from 1 to N. Each node has an integer weight. We will ask you to perform the following operation: u v : ask for how many different integers that represent the we…

COT2 - Count on a tree II http://www.spoj.com/problems/COT2/ #tree You are given a tree with N nodes. The tree nodes are numbered from 1 to N. Each node has an integer weight. We will ask you to perform the following operation: u v : ask for how many…