codeforces131D
Subway
A subway scheme, classic for all Berland cities is represented by a set of nstations connected by n passages, each of which connects exactly two stations and does not pass through any others. Besides, in the classic scheme one can get from any station to any other one along the passages. The passages can be used to move in both directions. Between each pair of stations there is no more than one passage.
Berland mathematicians have recently proved a theorem that states that any classic scheme has a ringroad. There can be only one ringroad. In other words, in any classic scheme one can find the only scheme consisting of stations (where any two neighbouring ones are linked by a passage) and this cycle doesn't contain any station more than once.
This invention had a powerful social impact as now the stations could be compared according to their distance from the ringroad. For example, a citizen could say "I live in three passages from the ringroad" and another one could reply "you loser, I live in one passage from the ringroad". The Internet soon got filled with applications that promised to count the distance from the station to the ringroad (send a text message to a short number...).
The Berland government decided to put an end to these disturbances and start to control the situation. You are requested to write a program that can determine the remoteness from the ringroad for each station by the city subway scheme.
Input
The first line contains an integer n (3 ≤ n ≤ 3000), n is the number of stations (and trains at the same time) in the subway scheme. Then n lines contain descriptions of the trains, one per line. Each line contains a pair of integers xi, yi (1 ≤ xi, yi ≤ n) and represents the presence of a passage from station xi to station yi. The stations are numbered from 1 to n in an arbitrary order. It is guaranteed that xi ≠ yi and that no pair of stations contain more than one passage. The passages can be used to travel both ways. It is guaranteed that the given description represents a classic subway scheme.
Output
Print n numbers. Separate the numbers by spaces, the i-th one should be equal to the distance of the i-th station from the ringroad. For the ringroad stations print number 0.
Examples
4
1 3
4 3
4 2
1 2
0 0 0 0
6
1 2
3 4
6 4
2 3
1 3
3 5
0 0 0 1 1 2 sol:这个数据范围实在是太友好了,O(n)bfs找环,n2dfs水过无压力,不知道(我猜)有更好的做法(树剖)可以nlogn
#include <bits/stdc++.h>
using namespace std;
typedef int ll;
inline ll read()
{
ll s=;
bool f=;
char ch=' ';
while(!isdigit(ch))
{
f|=(ch=='-'); ch=getchar();
}
while(isdigit(ch))
{
s=(s<<)+(s<<)+(ch^); ch=getchar();
}
return (f)?(-s):(s);
}
#define R(x) x=read()
inline void write(ll x)
{
if(x<)
{
putchar('-'); x=-x;
}
if(x<)
{
putchar(x+''); return;
}
write(x/);
putchar((x%)+'');
return;
}
#define W(x) write(x),putchar(' ')
#define Wl(x) write(x),putchar('\n')
const int N=,M=,inf=0x3f3f3f3f;
int n;
namespace Pic
{
int tot=,Next[M],to[M],head[N],Deg[N]; inline void add(int x,int y);
inline void dfs(int x,int fa);
inline void Solve(); inline void add(int x,int y)
{
Next[++tot]=head[x];
to[tot]=y;
head[x]=tot;
Deg[y]++;
}
bool Vis[N];
inline void bfs()
{
int i;
queue<int>Queue;
for(i=;i<=n;i++) if(Deg[i]==)
{
Queue.push(i);
Vis[i]=;
}
while(!Queue.empty())
{
int x=Queue.front(); Queue.pop();
for(i=head[x];i;i=Next[i]) if(!Vis[to[i]])
{
Deg[to[i]]--;
if(Deg[to[i]]<)
{
Vis[to[i]]=;
Queue.push(to[i]);
}
}
}
}
int Ans[N];
bool Huan[N];
inline int dfs(int x,int fa,int Dis)
{
if(Huan[x]) return Dis;
int i,res=inf;
for(i=head[x];i;i=Next[i]) if(to[i]!=fa)
{
res=min(res,dfs(to[i],x,Dis+));
}
return res;
}
inline void Solve()
{
int i;
bfs();
for(i=;i<=n;i++) if(!Vis[i]) Huan[i]=;
for(i=;i<=n;i++) Ans[i]=dfs(i,,);
for(i=;i<=n;i++) W(Ans[i]);
}
}
int main()
{
int i;
R(n);
for(i=;i<=n;i++)
{
int x,y; R(x); R(y);
Pic::add(x,y); Pic::add(y,x);
}
Pic::Solve();
return ;
}
/*
Input
4
1 3
4 3
4 2
1 2
Output
0 0 0 0 Input
6
1 2
3 4
6 4
2 3
1 3
3 5
Output
0 0 0 1 1 2
*/
codeforces131D的更多相关文章
随机推荐
- 如何使用git和ssh部署本地代码到服务器
一.首先设置好自己本地的Git用户名和密码: git config --global user.name "your name" git config --global user. ...
- DSAPI Wifi热点的扫描与连接
使用DSAPI扫描和连接Wifi热点,支持连接隐藏的SSID. 效果演示: 代码如下: Private Wifi As New DSAPI.网络.Wifi Private Sub Button1_Cl ...
- DSAPI 菜单渲染
在本节,将演示DSAPI.菜单渲染功能.本功能支持对WINFORM菜单项的任意细节进行处理,使用配色方案进行渲染,默认配色方案为Visual Studio2012的黑色主题风格. 我们先来看一下未使用 ...
- phpstorm 代码注释后,撤销某段代码的注释的,快捷键是什么?
phpstorm 的代码注释有两种风格,一种是双斜杠,另一种是 /* ... */风格,两者的快捷键都是开关式(即按第一次为注释,再按一次为撤销注释),快捷键如下: 1.双斜杠注释 Ctrl + ...
- MongoDB学习(查找文档和其他数据查找操作)
理解Cursor对象和查询运算符 cursor对象 cursor对象相当于一个指针,可通过迭代它来访问MongdoDB数据库中的一组对象. 在使用 find() 方法查询时,返回的并非实际文档,而是一 ...
- VSCode 下载Models 报错
VSCode调试部分代码时,报错,提示不能自动获取Models.报错信息如下. go: golang.org/x/crypto@v0.-80db560fac1f: unrecognized impor ...
- 猴子选大王 (约瑟夫环)(c#)
猴子选大王问题: 一堆猴子都有编号,编号是1,2,3 ...m ,这群猴子(m个)按照1到m的顺序围坐一圈, 从第1开始数,每数到第n个,该猴子就要离开此圈,这样依次下来,直到圈中只剩下最后一只猴子, ...
- PostgreSQL10.1 linux 编译安装
一 安装准备 1.首先从官网下载PostgreSQL压缩包(也可以使用yum安装),我们这里使用的是10.1的版本 2.将文件上传到linux服务区目录(我们这里放在/root 中) 3.解压缩 ta ...
- Java 基本文件操作
Java 文件操作 , 这也是基于Java API 操作来实现的. 文件是操作系统管理外存数据管理的基本单位, 几乎所有的操作系统都有文件管理机制. 所谓文件, 是具有符号名而且在逻辑上具有完整意义的 ...
- requests库下载图片的方法
方法: 传入图片url,requests.get()方法请求一下,将源码以二进制的形式写在本地即可. 以前一直以为requests库中有特定的方法获取图片,类似urllib.request.urlre ...