dsu on tree 题目链接 点我跳转 题目大意 给定一棵 \(n\) 个节点的树,根节点为 \(1\).每个节点上有一个颜色 \(c_i\) \(m\) 次询问. 每次询问给出 \(u\) \(k\):询问在以 \(u\) 为根的子树中,出现次数 \(≥k\) 的颜色有多少种. 解题思路 可以开棵权值线段树 如果当前颜色出现的次数 \(cnt[i] = x\), 就把树的第 \(x\) 个位置的值 \(+ 1\) 那么对于每个询问的 \(k\) 输出树的第 \(k\) 个位置的值即可 AC…

题意:给定一棵树,每个节点有颜色,对于每个询问(u,k)询问以u为根节点的子树下有多少种颜色出现次数>=k 因为是子树,跟dfs序有关,转化为一段区间,可以用莫队算法求解 直接用一个数组统计出现次数>=k的颜色 Code #include <cstdio> #include <algorithm> #include <cmath> #define N 100010 using namespace std; int n,m,A[N],bl[N],Ans[N],…

题目链接:375D - Tree and Queries 题目大意:给你一个有n个点的树,每个点都有其对应的颜色,给出m次询问(v,k),问v的子树中有多少种颜色至少出现k次 题解:先对所有的询问进行分类,即对所有相同的v合并到一起,这样就能转为离线处理(更新每个点的状态时同时求出答案) 开两个map<int,int>,cnt[i][j]表示 i 节点的子树中 j 颜色出现了多少次,f[i][j]则表示 i 节点的子树中至少出现 j 次的颜色个数.dfs的时候暴力枚举所有颜色合并能够得出正确答…

题目链接  Tree and Queries 题目大意  给出一棵树和每个节点的颜色.每次询问$vj, kj$ 你需要回答在以$vj$为根的子树中满足条件的的颜色数目, 条件:具有该颜色的节点数量至少为$kj$. (莫队居然可以过) 首先转$DFS$序,这样就变成了区间查询. 然后直接套用莫队,求出每次询问状态下的$t[],t[k]$表示当前区间内拥有$k$个节点的颜色数量. 然后统计$t[k] + t[k + 1], ..., t[MAX]$即可,这个过程用树状数组维护. #include <…

Tree and Queries 题意:有一颗以1号节点为根的树,每一个节点有一个自己的颜色,求出节点v的子数上颜色出现次数>=k的颜色种类. 题解:使用莫队处理这个问题,将树转变成DFS序区间,然后就是开一个数据记录下出现次数为k次的颜色数目,查询的时候直接返回这个数组中的对应的值就行了. 注意的就是记得将节点的颜色传递给dfs序对应位置的颜色. 这个忘记了找了好久的bug. 代码: #include<bits/stdc++.h> using namespace std; #defin…

Description You have a rooted tree consisting of n vertices. Each vertex of the tree has some color. We will assume that the tree vertices are numbered by integers from 1 to n. Then we represent the color of vertex v as cv. The tree root is a vertex…

题意翻译 给出一棵 n 个结点的树,每个结点有一个颜色 c i . 询问 q 次,每次询问以 v 结点为根的子树中,出现次数 ≥k 的颜色有多少种.树的根节点是1. 感谢@elijahqi 提供的翻译 题目描述 You have a rooted tree consisting of n n n vertices. Each vertex of the tree has some color. We will assume that the tree vertices are numbered…

You have a rooted tree consisting of n vertices. Each vertex of the tree has some color. We will assume that the tree vertices are numbered by integers from 1 to n. Then we represent the color of vertex v as cv. The tree root is a vertex with number…

Discription You have a rooted tree consisting of n vertices. Each vertex of the tree has some color. We will assume that the tree vertices are numbered by integers from 1 to n. Then we represent the color of vertex v as cv. The tree root is a vertex…

You have a rooted tree consisting of n vertices. Each vertex of the tree has some color. We will assume that the tree vertices are numbered by integers from 1 to n. Then we represent the color of vertex v as cv. The tree root is a vertex with number…