一棵树,结点树为n,根结点为r.每个结点都有一个权值ci,开始时间为0,每染色一个结点需要耗时1,每个结点的染色代价为ci*ti(ti为当前的时间),每个结点只有在父结点已经被染色的条件下才能被染色.求染完整棵树需要花费的最小代价. 找出当前最大子节点和其父节点合并成新的节点直到点集中只剩一个节点因为合并时将子节点的权值加在父节点上则 每次更新 答案加上当前子节点的权值乘上父节点的花费时间,这个很神奇 因为合并后,当对其父节点操作时也会重复加上子节点权值,即累加起来等同于每一个节点的最初权值乘上…

Bob intends to color the nodes of a tree with a pen. The tree consists of NN nodes. These nodes are numbered 1,2,...,N1,2,...,N. The root of the tree is node 11. The initial color of each node is white. Bob can use one unit energy to color one node i…

这道题细节真的非常多 首先能够想到a和b的最优策略一定是沿着a和b在树上的链走,走到某个点停止,然后再依次占据和这个点邻接的边 所以,解决这道题的过程例如以下: 预处理阶段: step 1:取随意一个点为根节点.找出父子关系而且对这个树进行dp.求出从某个节点出发往下所包括的全部边的权值总和  复杂度O(n) step 2:从tree dp 的结果中计算对于某个节点.从某条边出发所包括的边的综合.而且对其从大到小进行排序 复杂度O(n*logn) step 3:dfs求出这颗树的欧拉回路,以及每…

/* 十分巧妙的二分 题意选最少的点涂色 使得满足输入信息: 1 x的子树涂色数不少于y 2 x的子树外面涂色数不少于y 我们若是把2转化到子树内最多涂色多少 就可以维护这个最小和最大 如果我们二分出了答案 就可以完成转化 转化后也恰好可以判断二分是否合法 */ #include<cstdio> #include<cstring> #include<iostream> #define maxn 100010 using namespace std; int T,n,m,…

HDU.1556 Color the ball (线段树 区间更新 单点查询) 题意分析 注意一下pushdown 和 pushup 模板类的题还真不能自己套啊,手写一遍才行 代码总览 #include <bits/stdc++.h> #define nmax 200000 using namespace std; struct Tree{ int l,r,val; int lazy; int mid(){ return (l+r)>>1; } }; Tree tree[nmax&…

贪心....                    Color a Tree Time Limit: 1000MS   Memory Limit: 30000K Total Submissions: 6647   Accepted: 2249 Description Bob is very interested in the data structure of a tree. A tree is a directed graph in which a special node is single…

Color the ball Time Limit: 9000/3000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 8984    Accepted Submission(s): 4594 Problem Description N个气球排成一排,从左到右依次编号为1,2,3....N.每次给定2个整数a b(a <= b),lele便为骑上他的“小飞鸽"牌电动车从气球…

Color the ball Time Limit: 9000/3000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 7941    Accepted Submission(s): 4070 Problem Description N个气球排成一排,从左到右依次编号为1,2,3....N.每次给定2个整数a b(a <= b),lele便为骑上他的“小飞鸽"牌电动车从气球…

Color a Tree Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 828    Accepted Submission(s): 272 Problem DescriptionBob is very interested in the data structure of a tree. A tree is a directed gr…

Dylans loves tree Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others)Total Submission(s): 1444    Accepted Submission(s): 329 Problem Description Dylans is given a tree with N nodes. All nodes have a value A[i].Nodes…