C. Andryusha and Colored Balloons
2 seconds
256 megabytes
standard input
standard output
Andryusha goes through a park each day. The squares and paths between them look boring to Andryusha, so he decided to decorate them.
The park consists of n squares connected with (n - 1) bidirectional paths in such a way that any square is reachable from any other using these paths. Andryusha decided to hang a colored balloon at each of the squares. The baloons' colors are described by positive integers, starting from 1. In order to make the park varicolored, Andryusha wants to choose the colors in a special way. More precisely, he wants to use such colors that if a, b and c are distinct squares that a and b have a direct path between them, and b and c have a direct path between them, then balloon colors on these three squares are distinct.
Andryusha wants to use as little different colors as possible. Help him to choose the colors!
The first line contains single integer n (3 ≤ n ≤ 2·105) — the number of squares in the park.
Each of the next (n - 1) lines contains two integers x and y (1 ≤ x, y ≤ n) — the indices of two squares directly connected by a path.
It is guaranteed that any square is reachable from any other using the paths.
In the first line print single integer k — the minimum number of colors Andryusha has to use.
In the second line print n integers, the i-th of them should be equal to the balloon color on the i-th square. Each of these numbers should be within range from 1 to k.
3
2 3
1 3
3
1 3 2
5
2 3
5 3
4 3
1 3
5
1 3 2 5 4
5
2 1
3 2
4 3
5 4
3
1 2 3 1 2
In the first sample the park consists of three squares: 1 → 3 → 2. Thus, the balloon colors have to be distinct.
Illustration for the first sample.
In the second example there are following triples of consequently connected squares:
- 1 → 3 → 2
- 1 → 3 → 4
- 1 → 3 → 5
- 2 → 3 → 4
- 2 → 3 → 5
- 4 → 3 → 5
We can see that each pair of squares is encountered in some triple, so all colors have to be distinct.
Illustration for the second sample.
In the third example there are following triples:
- 1 → 2 → 3
- 2 → 3 → 4
- 3 → 4 → 5
We can see that one or two colors is not enough, but there is an answer that uses three colors only.
Illustration for the third sample.
思路:dfs;
每个节点只会由他的父亲节点,祖父节点,还有兄弟节点来影响,那么dfs,然后每层从1开始找不是父亲节点,祖父节点,还有兄 弟节值的最小值,复杂度O(n);
1 #include<iostream>
2 #include<stdlib.h>
3 #include<queue>
4 #include<string.h>
5 #include<stdio.h>
6 #include<stack>
7 #include<vector>
8 using namespace std;
9 vector<int>vec[1000000];
10 int minn = 0;
11 int ask[1000000];
12 void dfs(int n,int fa);
13 int main(void)
14 {
15 int n;
16 scanf("%d",&n);
17 for(int i = 0; i <n-1; i++)
18 {
19 int x,y;
20 scanf("%d %d",&x,&y);
21 vec[x].push_back(y);
22 vec[y].push_back(x);
23 }ask[1] = 1;
24 dfs(1,0);
25 printf("%d\n",minn);
26 printf("%d",ask[1]);
27 for(int i = 2; i <= n; i++)
28 printf(" %d",ask[i]);
29 printf("\n");
30 return 0;
31 }
32 void dfs(int n,int fa)
33 {
34 int cnt = 1;
35 for(int i = 0; i <vec[n].size(); i++)
36 {
37 int ic = vec[n][i];
38 if(ic != fa)
39 {
40 while(cnt == ask[fa]||cnt == ask[n])
41 {
42 cnt++;
43 }
44
45 ask[ic] = cnt++;
46 dfs(ic,n);
47 }
48 }
49 minn = max(minn,cnt-1);
50 }
C. Andryusha and Colored Balloons的更多相关文章
- code force 403C.C. Andryusha and Colored Balloons
C. Andryusha and Colored Balloons time limit per test 2 seconds memory limit per test 256 megabytes ...
- Codeforces 782C. Andryusha and Colored Balloons 搜索
C. Andryusha and Colored Balloons time limit per test:2 seconds memory limit per test:256 megabytes ...
- Codeforces Round #403 (Div. 2, based on Technocup 2017 Finals) C Andryusha and Colored Balloons
地址:http://codeforces.com/contest/782/problem/C 题目: C. Andryusha and Colored Balloons time limit per ...
- codeforces781A Andryusha and Colored Balloons
本文版权归ljh2000和博客园共有,欢迎转载,但须保留此声明,并给出原文链接,谢谢合作. 本文作者:ljh2000 作者博客:http://www.cnblogs.com/ljh2000-jump/ ...
- AC日记——Andryusha and Colored Balloons codeforces 780c
C - Andryusha and Colored Balloons 思路: 水题: 代码: #include <cstdio> #include <cstring> #inc ...
- CodeForces - 780C Andryusha and Colored Balloons(dfs染色)
Andryusha goes through a park each day. The squares and paths between them look boring to Andryusha, ...
- CF781A Andryusha and Colored Balloons
题意: Andryusha goes through a park each day. The squares and paths between them look boring to Andryu ...
- 782C. Andryusha and Colored Balloons DFS
Link 题意: 给出一棵树,要求为其染色,并且使任意节点都不与距离2以下的节点颜色相同 思路: 直接DFS.由某节点出发的DFS序列,对于其个儿子的cnt数+1,那么因为DFS遍历的性质可保证兄弟结 ...
- 【贪心】【DFS】Codeforces Round #403 (Div. 2, based on Technocup 2017 Finals) C. Andryusha and Colored Balloons
从任意点出发,贪心染色即可. #include<cstdio> #include<algorithm> using namespace std; int v[200010< ...
随机推荐
- mac 下 如何在同一窗口打开多个终端并实现快捷键切换
相信大家编代码的时候都会遇到,每次需要在头文件,库文件和源码文件中编代码的时候,总是需要在几个文件中切换来切换去的,而且一个文件就一个终端窗口,每次都要用鼠标点来点去,非常麻烦,所以如果能把这几个文件 ...
- 33、搜索旋转排序数组 | 算法(leetode,附思维导图 + 全部解法)300题
零 标题:算法(leetode,附思维导图 + 全部解法)300题之(33)搜索旋转排序数组 一 题目描述! 题目描述 二 解法总览(思维导图) 三 全部解法 1 方案1 1)代码: // 方案1 & ...
- 【模板】有源汇有上下界最大流(网络流)/ZOJ3229
先导知识 无源汇有上下界可行流 题目链接 https://vjudge.net/problem/ZOJ-3229 https://www.luogu.com.cn/problem/P5192 (有改动 ...
- Label -- 跳出循环的思路
let num = 0 ; outPoint: //label for (let i = 0; i < 10; i++) { for ( let j = 0; j < 10; j++) { ...
- 日常Java 2021/10/31
泛型类 泛型类的声明和非泛型类的声明类似,除了在类名后面添加了类型参数声明部分.和迈型方法一样,泛型类的类型参数声明部分也包含一个或多个类型参数,参数间用逗号隔开.一个泛型参数,也被称为一个类型变量, ...
- 如何在 ASP.NET Core 中构建轻量级服务
在 ASP.NET Core 中处理 Web 应用程序时,我们可能经常希望构建轻量级服务,也就是没有模板或控制器类的服务. 轻量级服务可以降低资源消耗,而且能够提高性能.我们可以在 Startup 或 ...
- Netty之Channel*
Netty之Channel* 本文内容主要参考**<<Netty In Action>> ** 和Netty的文档和源码,偏笔记向. 先简略了解一下ChannelPipelin ...
- 【转载】HBase基本数据操作详解【完整版,绝对精品】
转载自: http://blog.csdn.net/u010967382/article/details/37878701 概述 对于建表,和RDBMS类似,HBase也有namespace的概念,可 ...
- django中的filter(), all(), get()
1. 类名.objects中的get(), filter(), all() 的区别 结论: (1)all()返回的是QuerySet对象,程序并没有真的在数据库中执行SQL语句查询数据,但支持迭代,使 ...
- 【leetcode】565. Array Nesting
You are given an integer array nums of length n where nums is a permutation of the numbers in the ra ...