标签：time iss ack cst nbsp limit join std hat
How Many Tables
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 35580 Accepted Submission(s): 17707
Problem Description
Today is Ignatius‘ birthday. He invites a lot of friends. Now it‘s dinner time. Ignatius wants to know how many tables he needs at least. You have to notice that not all the friends know each other, and all the friends do not want to stay with strangers.
One important rule for this problem is that if I tell you A knows B, and B knows C, that means A, B, C know each other, so they can stay in one table.
For example: If I tell you A knows B, B knows C, and D knows E, so A, B, C can stay in one table, and D, E have to stay in the other one. So Ignatius needs 2 tables at least.
Input
The input starts with an integer T(1<=T<=25) which indicate the number of test cases. Then T test cases follow. Each test case starts with two integers N and M(1<=N,M<=1000). N indicates the number of friends, the friends are marked from 1 to N. Then M lines follow. Each line consists of two integers A and B(A!=B), that means friend A and friend B know each other. There will be a blank line between two cases.
Output
For each test case, just output how many tables Ignatius needs at least. Do NOT print any blanks.
Sample Input
Sample Output
2
4
http://acm.hdu.edu.cn/showproblem.php?pid=1213 题目链接
最最基础的并查集。
题意：每个人相互认识，把有“认识”这种关系的人放在一张桌子上。（很水）
1 #include<cstdio>
2 #include<iostream>
3 #include<cmath>
4 #include<cstring>
5 #include<cstdlib>
6 #include<queue>
7 #include<map>
8 #include<algorithm>
9 #include<set>
10 #include<stack>
11 using namespace std;
12 int k=0,pr[1005];
13 int Find(int x)
14 {
15 if(x!=pr[x])pr[x]=Find(pr[x]);
16 return pr[x];
17 }
18 /*int Find(int x)
19 {
20 int p,temp;
21 p=x;
22 while(x!=pr[x])
23 x=pr[x];
24 while(p!==x)
25 {
26 temp=pr[p];
27 pr[p]=x;
28 p=temp;
29 }
30 }*/
31 void join(int x,int y)
32 {
33 int p;p=Find(x);
34 int q;q=Find(y);
35 if(p!=q)pr[q]=p;
36 }
37 int main()
38 {
39 int T;
40 cin>>T;
41 while(T--)
42 {
43 int sum=0;
44 int a,b;
45 cin>>a>>b;
46 for(int i=1;i<=a;i++)
47 {
48 pr[i]=i;
49 }
50 for(int i=1;i<=b;i++)
51 {
52 int q,p;
53 cin>>q>>p;
54 p=Find(p);
55 q=Find(q);
56 if(q!=p)join(p,q);
57 }
58 for(int i=1;i<=a;i++)
59 {
60 if(pr[i]==i)sum++;
61 }
62 cout<<sum;
63 cout<<endl;
64 }
65 return 0;
66
67 }
HDU-1213 How Many Tables（并查集）
标签：time iss ack cst nbsp limit join std hat
原文地址：http://www.cnblogs.com/SparkPhoneix/p/8016351.html
