http://www.lydsy.com/JudgeOnline/problem.php?id=1602 || https://www.luogu.org/problem/show?pid=2912 题目描述 N头牛(2<=n<=1000)别人被标记为1到n,在同样被标记1到n的n块土地上吃草,第i头牛在第i块牧场吃草. 这n块土地被n-1条边连接. 奶牛可以在边上行走,第i条边连接第Ai,Bi块牧场,第i条边的长度是Li(1<=Li<=10000). 这些边被安排成任意两头奶牛都…

P2912 [USACO08OCT]牧场散步Pasture Walking 题目描述 The N cows (2 <= N <= 1,000) conveniently numbered 1..N are grazing among the N pastures also conveniently numbered 1..N. Most conveniently of all, cow i is grazing in pasture i. Some pairs of pastures are…

题目描述 The N cows (2 <= N <= 1,000) conveniently numbered 1..N are grazing among the N pastures also conveniently numbered 1..N. Most conveniently of all, cow i is grazing in pasture i. Some pairs of pastures are connected by one of N-1 bidirectional…

题目描述 The N cows (2 <= N <= 1,000) conveniently numbered 1..N are grazing among the N pastures also conveniently numbered 1..N. Most conveniently of all, cow i is grazing in pasture i. Some pairs of pastures are connected by one of N-1 bidirectional…

1602: [Usaco2008 Oct]牧场行走 Time Limit: 5 Sec  Memory Limit: 64 MBSubmit: 379  Solved: 216[Submit][Status][Discuss] Description N头牛(2<=n<=1000)别人被标记为1到n,在同样被标记1到n的n块土地上吃草,第i头牛在第i块牧场吃草. 这n块土地被n-1条边连接. 奶牛可以在边上行走,第i条边连接第Ai,Bi块牧场,第i条边的长度是Li(1<=Li<=1…

一棵树..或许用LCA比较好吧...但是我懒...写了个dijkstra也过了.. ---------------------------------------------------------------------------- #include<cstdio> #include<algorithm> #include<queue> #include<cstring> #include<iostream>   #define rep( i…

题面:[USACO08OCT]牧场散步Pasture Walking 题解:LCA模版题 代码: #include<cstdio> #include<cstring> #include<iostream> using namespace std; ,max_log=; ][max_log+],edge_head[maxn+],num_edge=,c,Dep[maxn+],u,v,w,A,B; ]; struct Edge{ int to,nx,dis; }edge[(m…

Description N头牛(2<=n<=1000)别人被标记为1到n,在同样被标记1到n的n块土地上吃草,第i头牛在第i块牧场吃草. 这n块土地被n-1条边连接. 奶牛可以在边上行走,第i条边连接第Ai,Bi块牧场,第i条边的长度是Li(1<=Li<=10000). 这些边被安排成任意两头奶牛都可以通过这些边到达的情况,所以说这是一棵树. 这些奶牛是非常喜欢交际的,经常会去互相访问,他们想让你去帮助他们计算Q(1<=q<=1000)对奶牛之间的距离. Input *…

题意:id=1602">链接 方法:深搜暴力 解析: 这题刚看完还有点意思,没看范围前想了想树形DP,只是随便画个图看出来是没法DP的,所以去看范围. woc我没看错范围?果断n^2暴力啊.想个卵. 于是写了暴力,暴力预处理每两个点间距离就好了. 尽管比别人慢了100ms?无卵用. 然后查了下正解,正解是求lca,最好还是设1为根,dis[i]代表根到i的距离,则对于询问x,y的答案就是dis[x]+dis[y]-2*dis[lca(x,y)]. 看起来好高端,然而暴力大法好! 代码: #…

翻翻吴大神的刷题记录翻到的... 乍一看是一个树链剖分吓瓜我...难不成吴大神14-10-28就会了树剖?orz... 再一看SB暴力都可过... 然后一看直接树上倍增码个就好了... 人生真是充满着大起大落= =! 擦树上倍增不会写了= =!... 写个STLCA算了...…