首页 > 代码库 > HDU 1213 How Many Tables (并查集)
HDU 1213 How Many Tables (并查集)
How Many Tables
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 14683 Accepted Submission(s): 7187
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.
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
2 5 3 1 2 2 3 4 5 5 1 2 5
Sample Output
2 4
就是最后要请多少桌的客人,并查集:
#include<iostream> #include<stdio.h> #include<string.h> using namespace std; int pre[1010]; int union_find(int node) { int leaf=node; while(node!=pre[node])node=pre[node]; while(leaf!=node) { int t_p=pre[leaf]; pre[leaf]=node; leaf=t_p; } return node; } int main(int argc, char *argv[]) { // freopen("1213.in","r",stdin); int T;//测试用例数量T(1<=T<=25) int N,M;//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.(1<=N,M<=1000) int a,b; scanf("%d",&T); while(T--) { scanf("%d %d",&N,&M); memset(pre,0,sizeof(pre)); int total=N; for(int i=1;i<=N;++i) pre[i]=i; while(M--) { scanf("%d %d",&a,&b); int p=union_find(a); int q=union_find(b); if(p!=q){ pre[p]=q; total--; } } printf("%d\n",total); } return 0; }
HDU 1213 How Many Tables (并查集)
声明:以上内容来自用户投稿及互联网公开渠道收集整理发布,本网站不拥有所有权,未作人工编辑处理,也不承担相关法律责任,若内容有误或涉及侵权可进行投诉: 投诉/举报 工作人员会在5个工作日内联系你,一经查实,本站将立刻删除涉嫌侵权内容。