2017 ICPC/ACM 沈阳区域赛HDU6228
color mini bio log desc lease all amp fin
Tree
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 262144/262144 K (Java/Others)
Total Submission(s): 373 Accepted Submission(s): 254
Problem Description
Consider a un-rooted tree T which is not the biological significance of tree or plant, but a tree as an undirected graph in graph theory with n nodes, labelled from 1 to n. If you cannot understand the concept of a tree here, please omit this problem.
Now we decide to colour its nodes with k distinct colours, labelled from 1 to k. Then for each colour i = 1, 2, · · · , k, define Ei as the minimum subset of edges connecting all nodes coloured by i. If there is no node of the tree coloured by a specified colour i, Ei will be empty.
Try to decide a colour scheme to maximize the size of E1 ∩ E2 · · · ∩ Ek, and output its size.
Input
The first line of input contains an integer T (1 ≤ T ≤ 1000), indicating the total number of test cases.
For each case, the first line contains two positive integers n which is the size of the tree and k (k ≤ 500) which is the number of colours. Each of the following n - 1 lines contains two integers x and y describing an edge between them. We are sure that the given graph is a tree.
The summation of n in input is smaller than or equal to 200000.
Output
For each test case, output the maximum size of E1 ∩ E1 ... ∩ Ek.
Sample Input
3
4 2
1 2
2 3
3 4
4 2
1 2
1 3
1 4
6 3
1 2
2 3
3 4
3 5
6 2
Sample Output
题意 给树节点染色
直接dfs搜一遍就好了
- #include <stdio.h>
- #include <math.h>
- #include <string.h>
- #include <stdlib.h>
- #include <iostream>
- #include <sstream>
- #include <algorithm>
- #include <string>
- #include <queue>
- #include <ctime>
- #include <vector>
- using namespace std;
- const int maxn= 1e5+5;
- const int maxm= 1e6+5;
- const int inf = 0x3f3f3f3f;
- typedef long long ll;
- vector<int> G[maxn];
- int n,k,ans;
- int siz[maxn];
- void dfs(int x,int fa)
- {
- siz[x]=1;
- for(int i=0;i<G[x].size();i++)
- {
- int w=G[x][i];
- if(w!=fa)
- {
- dfs(w,x);
- siz[x]+=siz[w];
- }
- }
- if(siz[x]>=k&&n-siz[x]>=k)
- ans++;
- }
- int main()
- {
- int t;
- scanf("%d",&t);
- while(t--)
- {
- scanf("%d%d",&n,&k);
- int u,v;
- for(int i=1;i<=n;i++)
- G[i].clear();
- for(int i=1;i<n;i++)
- {
- scanf("%d%d",&u,&v);
- G[u].push_back(v);
- G[v].push_back(u);
- }
- ans=0;
- dfs(1,0);
- printf("%d\n",ans);
- }
- }
2017 ICPC/ACM 沈阳区域赛HDU6228
color mini bio log desc lease all amp fin
原文:http://www.cnblogs.com/stranger-/p/7841226.html
来源: http://www.bubuko.com/infodetail-2396325.html