这题本来是想放在educational round 3的题解里的,但觉得很有意思就单独拿出来写了 题目链接:609E - Minimum spanning tree for each edge 题目大意:n个点,m条边,对每条边,询问包含此边的最小生成树的边权之和 题解:大部分人都是用LCA写的,这里提供一个更为精妙的做法. 模拟Kruskal算法建MST的过程,先将m条边按边权排序,依次进行判断.若点对(u,v)属于同一个连通块,则加入边{u,v,w}后会形成一个环,把环中最大的边换成w会多产…

E. Minimum spanning tree for each edge time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Connected undirected weighted graph without self-loops and multiple edges is given. Graph contains n …

题意:一个无向图联通中,求包含每条边的最小生成树的值(无自环,无重边) 分析:求出这个图的最小生成树,用最小生成树上的边建图 对于每条边,不外乎两种情况 1:该边就是最小生成树上的边,那么答案显然 2:该边不在最小生成树上,那么进行路径查询,假设加入这条边,那么形成一个环,删去这个环上除该边外的最大权值边,形成一棵树 树的权值即为答案.(并不需要真正加入这条边) 注:其实用树链剖分和LCA都可以,选择自己熟悉的写就行,我写的树链剖分 #include<cstdio> #include<c…

题目链接 给一个n个节点m条边的树, 每条边有权值, 输出m个数, 每个数代表包含这条边的最小生成树的值. 先将最小生成树求出来, 把树边都标记. 然后对标记的边的两个端点, 我们add(u, v), add(v, u). 对于每一次输出, 如果这条边被标记了, 那么直接输出mst的值. 否则, 加上这条边之后一定会出现一个环, 我们就把环上的最长的那条边删掉. 查询最长的那条边可以用树链剖分. #include <iostream> #include <vector> #incl…

最小生成树,lca(树链剖分(太难搞,不会写)) 问存在这条边的最小生成树,2种情况.1.这条边在原始最小生成树上.2.加上这条半形成一个环(加上),那么就找原来这条边2端点间的最大边就好(减去).(sum+val-max) (代码冗长) #include<bits/stdc++.h> #define LL long long #define N 100005 using namespace std; inline int ra() { ,f=; char ch=getchar(); ; ch…

E. Minimum spanning tree for each edge   Connected undirected weighted graph without self-loops and multiple edges is given. Graph contains n vertices and m edges. For each edge (u, v) find the minimal possible weight of the spanning tree that contai…

E. Minimum spanning tree for each edge time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Connected undirected weighted graph without self-loops and multiple edges is given. Graph contains n …

E. Minimum spanning tree for each edge 题目连接: http://www.codeforces.com/contest/609/problem/E Description Connected undirected weighted graph without self-loops and multiple edges is given. Graph contains n vertices and m edges. For each edge (u, v) f…

E. Minimum spanning tree for each edge time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Connected undirected weighted graph without self-loops and multiple edges is given. Graph contains n …

E. Minimum spanning tree for each edge 题目连接: http://www.codeforces.com/contest/609/problem/E Description Connected undirected weighted graph without self-loops and multiple edges is given. Graph contains n vertices and m edges. For each edge (u, v) f…