Codeforces Round #408 (Div. 2) D
Description
Inzane finally found Zane with a lot of money to spare, so they together decided to establish a country of their own.
Ruling a country is not an easy job. Thieves and terrorists are always ready to ruin the country's peace. To fight back, Zane and Inzane have enacted a very effective law: from each city it must be possible to reach a police station by traveling at most d kilometers along the roads.

There are n cities in the country, numbered from 1 to n, connected only by exactly n - 1 roads. All roads are 1 kilometer long. It is initially possible to travel from a city to any other city using these roads. The country also has k police stations located in some cities. In particular, the city's structure satisfies the requirement enforced by the previously mentioned law. Also note that there can be multiple police stations in one city.
However, Zane feels like having as many as n - 1 roads is unnecessary. The country is having financial issues, so it wants to minimize the road maintenance cost by shutting down as many roads as possible.
Help Zane find the maximum number of roads that can be shut down without breaking the law. Also, help him determine such roads.
The first line contains three integers n, k, and d (2 ≤ n ≤ 3·105, 1 ≤ k ≤ 3·105, 0 ≤ d ≤ n - 1) — the number of cities, the number of police stations, and the distance limitation in kilometers, respectively.
The second line contains k integers p1, p2, ..., pk (1 ≤ pi ≤ n) — each denoting the city each police station is located in.
The i-th of the following n - 1 lines contains two integers ui and vi (1 ≤ ui, vi ≤ n, ui ≠ vi) — the cities directly connected by the road with index i.
It is guaranteed that it is possible to travel from one city to any other city using only the roads. Also, it is possible from any city to reach a police station within d kilometers.
In the first line, print one integer s that denotes the maximum number of roads that can be shut down.
In the second line, print s distinct integers, the indices of such roads, in any order.
If there are multiple answers, print any of them.
6 2 4
1 6
1 2
2 3
3 4
4 5
5 6
1
5
6 3 2
1 5 6
1 2
1 3
1 4
1 5
5 6
2
4 5
In the first sample, if you shut down road 5, all cities can still reach a police station within k = 4 kilometers.
In the second sample, although this is the only largest valid set of roads that can be shut down, you can print either 4 5 or 5 4 in the second line.
题意:告诉你哪些点是警察局,由于资金原因需要删除一些道路,不过需要满足其他点到警察局的距离小于d
解法:BFS,其实d是无关的,我们只需要根据每个警察局进行BFS遍历,然后哪些路没走过就输出,(为什么d无关,我也不知道)
#include<bits/stdc++.h>
using namespace std;
int vis[];
int n,k,m,d;
int flag[];
queue<int>q;
vector<pair<int,int>>p[];
int main()
{
scanf("%d%d%d",&n,&m,&d);
for(int i=;i<=m;i++)
{
int num;
scanf("%d",&num);
vis[num]=;
q.push(num);
}
for(int i=;i<=n-;i++)
{
int u,v;
scanf("%d%d",&v,&u);
p[u].push_back({v,i});
p[v].push_back({u,i});
}
while(!q.empty())
{
int x=q.front();
q.pop();
// cout<<x<<endl;
for(int i=;i<p[x].size();i++)
{
int ans=p[x][i].first;
int cnt=p[x][i].second;
if(vis[ans]) continue;
vis[ans]=;
flag[cnt]=;
q.push(ans);
}
}
//cout<<endl;
int cot=;
for(int i=;i<n;i++)
{
if(!flag[i])
{
cot++;
}
}
printf("%d\n",cot);
for(int i=;i<n;i++)
{
if(!flag[i])
{
printf("%d ",i);
}
}
return ;
}
Codeforces Round #408 (Div. 2) D的更多相关文章
- Codeforces Round #408 (Div. 2)(A.水,B,模拟)
A. Buying A House time limit per test:2 seconds memory limit per test:256 megabytes input:standard i ...
- Codeforces Round #408 (Div. 2)C. Bank Hacking(STL)
题目链接:http://codeforces.com/problemset/problem/796/C 题目大意:有n家银行,第一次可以攻击任意一家银行(能量低于自身),跟被攻击银行相邻或者间接相邻( ...
- Codeforces Round #408 (Div. 2) C. Bank Hacking
http://codeforces.com/contest/796/problem/C Although Inzane successfully found his beloved bone, Zan ...
- Codeforces Round #408 (Div. 2) A B C 模拟 模拟 set
A. Buying A House time limit per test 2 seconds memory limit per test 256 megabytes input standard i ...
- Codeforces Round #408 (Div. 2) D - Police Stations
地址:http://codeforces.com/contest/796/problem/D 题目: D. Police Stations time limit per test 2 seconds ...
- Codeforces Round #408 (Div. 2) B
Description Zane the wizard is going to perform a magic show shuffling the cups. There are n cups, n ...
- Codeforces Round #408 (Div. 2)
C. Bank Hacking 题目大意:给出一棵n个节点的树,每个节点有一个权值,删掉一个点的代价为当前这个点的权值,并且会使其相邻点和距离为2且中间隔着未被删除的点的点权值加1,现在选一个点开始删 ...
- Codeforces Round #408 (Div. 2) 题解【ABCDE】
A - Buying A House 题意:给你n个房间,妹子住在第m个房间,你有k块钱,你想买一个离妹子最近的房间.其中相邻的房间之间距离为10,a[i]=0表示已经被别人买了. 题解:扫一遍更新答 ...
- Codeforces Round #408 (Div. 2) D. Police Stations(最小生成树+构造)
传送门 题意 n个点有n-1条边相连,其中有k个特殊点,要求: 删去尽可能多的边使得剩余的点距特殊点的距离不超过d 输出删去的边数和index 分析 比赛的时候想不清楚,看了别人的题解 一道将1个联通 ...
- Codeforces Round #408 (Div. 2) C.Bank Hacking(二分)
传送门 题意 给出n个银行,银行之间总共有n-1条边,定义i与j有边相连为neighboring,i到j,j到k有边,则定义i到k的关系为semi- neighboring, 每家银行hack的难度为 ...
随机推荐
- CodeForces 559C Gerald and Gia (格路+容斥+DP)
CodeForces 559C Gerald and Gia 大致题意:有一个 \(N\times M\) 的网格,其中有些格子是黑色的,现在需要求出从左上角到右下角不经过黑色格子的方案数(模 \(1 ...
- poj 1821 Fence(单调队列优化DP)
poj 1821 Fence \(solution:\) 这道题因为每一个粉刷的人都有一块"必刷的木板",所以可以预见我们的最终方案里的粉刷匠一定是按其必刷的木板的顺序排列的.这就 ...
- jquery和CSS3带倒影的3D万花筒旋转动画特效效果演示
<!DOCTYPE html> <html> <head> <title></title> <meta charset='utf-8' ...
- react native与原生的交互
一.交互依赖的重要组件 react native 中如果想要调用ios 中相关的方法,必须依赖一个重要的组件nativemodules import { NativeModules } from ' ...
- react项目中的注意点
一.ES6 的编译方法 目前主流的浏览器还不支持ES6. 现在一般采用webpack 和 <script type="text/babel">对jsx 语法进行编译, ...
- Git 对比两分支中同一文件
语法 git diff <分支名> <分支名> -- 文件名 git diff branch1 branch2 -- path/file.txt 案例 git diff ori ...
- jsch文件下载功能
转载:http://www.cnblogs.com/longyg/archive/2012/06/25/2561332.html 上一篇讲述了使用JSch实现文件上传的功能,这一篇主要讲述一下JSch ...
- MyBatis学习 之 七、mybatis各种数据库的批量修改
MyBatis的update元素的用法与insert元素基本相同,因此本篇不打算重复了.本篇仅记录批量update操作的sql语句,懂得SQL语句,那么MyBatis部分的操作就简单了. 注意:下 ...
- MyBatis学习 之 六、insert操作返回主键
数据库操作怎能少了INSERT操作呢?下面记录MyBatis关于INSERT操作的笔记,以便日后查阅. 二. insert元素 属性详解 其属性如下: parameterType ,入参的全 ...
- AtCoder Beginner Contest 057
A题 分析:24进制转换 #include<iostream> using namespace std; int main() { int a,b; while(cin>>a& ...