How far away ? Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 10312    Accepted Submission(s): 3743 Problem Description There are n houses in the village and some bidirectional roads connecting…

How far away ? Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 25408    Accepted Submission(s): 10111 Problem Description There are n houses in the village and some bidirectional roads connectin…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=2586 题意:给出一棵n个节点的无根树,每条边有各自的权值.给出m个查询,对于每条查询返回节点u到v的最短路径的权值和,按查询顺序输出结果. 数据范围:n [2, 40000], m[1, 200] 思路:Tarjan算法:dfs遍历每个点,每遍历完 r 的一个孩子 c, 把 c 并入以 r 为祖先的集合,并处理 c 的所有查询 q:若qi的目标节点 v 已被遍历到,那么一定有lca(c, v) =…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=2586 LCA模版题. RMQ+LCA: #include <iostream> #include <cstdio> #include <cstring> #include <vector> using namespace std; ; typedef pair<int , int>P; vector <P> G[MAXN]; ] , ok…

题意:给定N个节点一棵树,现在要求询问任意两点之间的简单路径的距离,其实也就是最短路径距离. 析:用LCA问题的Tarjan算法,利用并查集的优越性,产生把所有的点都储存下来,然后把所有的询问也储存下来,然后从树根开始搜索这棵树, 在搜索子树的时候,把并查集的父结点不断更新,在搜索时计算答案,d[i] 表示从根结点到 i 结点的距离,然后分别计算到两个结点的距离, 再减去2倍的根结点到他们公共最近的结点距离,就OK了.不过这个题有个坑人的地方,不用输出那个空行,否则就是PE. 因为这个题询问比较…

Code: #include<cstdio> #include<cstring> #include<vector> #include<algorithm> using namespace std; const int maxn=40000+3; typedef long long ll; ll dis[maxn]; int son[maxn],siz[maxn],rank1[maxn],p[maxn],top[maxn]; struct Edge { int…

题意: N个点,形成一棵树,边有长度. M个询问,每个询问(a,b),询问a和b的距离 思路: 模板题,看代码.DFS预处理算出每个结点离根结点的距离. 注意: qhead[maxn],而不是qhead[maxm]. 输出用%I64d,不要用%lld. C++ RE后 尝试用 G++交. 代码: struct node{ int to,w,next,lca; }; int const maxn = 40005; int const maxm = 205; int fa[maxn]; int he…

HDU 2586 How far away ? Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 11320    Accepted Submission(s): 4119 Problem Description   There are n houses in the village and some bidirectional roads…

How far away ? Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 8712    Accepted Submission(s): 3047 Problem Description There are n houses in the village and some bidirectional roads connecting…

昨天写了HDU 3966 ,本来这道题是很好解得,结果我想用离线LCA 耍一把,结果发现离线LCA 没理解透,错了好多遍,终得AC ,这题比起 HDU 3966要简单,因为他不用动态查询.但是我还是错了好多遍  T^T... http://acm.split.hdu.edu.cn/showproblem.php?pid=5044 不多说了  思想不是很清楚的可以看一看我的上一篇博文 HDU 3966 直接贴代码 #include<iostream> #include<stdio.h>…