POJ 2492 A Bug's Life

最新推荐文章于 2022-04-03 23:46:16 发布

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最新推荐文章于 2022-04-03 23:46:16 发布

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分类专栏：数据结构

本文链接：https://blog.youkuaiyun.com/Rlt1296/article/details/51858198

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本文介绍了一种通过观察虫族互动来验证其性别行为假设的方法。利用并查集记录每只虫子的交互情况，确保没有同性互动发生。若发现同性互动，则假设不成立。

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Description

Background
Professor Hopper is researching the sexual behavior of a rare species of bugs. He assumes that they feature two different genders and that they only interact with bugs of the opposite gender. In his experiment, individual bugs and their interactions were easy to identify, because numbers were printed on their backs.
Problem
Given a list of bug interactions, decide whether the experiment supports his assumption of two genders with no homosexual bugs or if it contains some bug interactions that falsify it.

Input
The first line of the input contains the number of scenarios. Each scenario starts with one line giving the number of bugs (at least one, and up to 2000) and the number of interactions (up to 1000000) separated by a single space. In the following lines, each interaction is given in the form of two distinct bug numbers separated by a single space. Bugs are numbered consecutively starting from one.

Output
The output for every scenario is a line containing “Scenario #i:”, where i is the number of the scenario starting at 1, followed by one line saying either “No suspicious bugs found!” if the experiment is consistent with his assumption about the bugs’ sexual behavior, or “Suspicious bugs found!” if Professor Hopper’s assumption is definitely wrong.

Sample Input

2
3 3
1 2
2 3
1 3
4 2
1 2
3 4

Sample Output

Scenario #1:
Suspicious bugs found!

Scenario #2:
No suspicious bugs found!

Hint
Huge input,scanf is recommended.

开一个并查集，若交配，将两只虫子分别存入补集，并且每次检查两只虫子是否在同一集合中。
注意，要输出两个换行符。

#include<iostream>
#include<cstdio>
using namespace std;
int n,m,f[4001];
inline int fnd(int x)
{
    if(f[x]==x)
        return x;
    return f[x]=fnd(f[x]);
}
int main()
{
    int t;
    scanf("%d",&t);
    for(int g=1;g<=t;g++)
    {
        bool flg=0;
        scanf("%d%d",&n,&m);
        printf("Scenario #%d:\n",g);
        for(int i=1;i<=2*n;i++)
            f[i]=i;
        for(int i=1;i<=m;i++)
        {
            int x,y;
            scanf("%d%d",&x,&y);
            if(fnd(x)==fnd(y))
                flg=1;
            else
            {
                f[fnd(y+n)]=fnd(x);
                f[fnd(y)]=fnd(x+n);
            }
        }
        if(flg)
            printf("Suspicious bugs found!\n\n");
        else
            printf("No suspicious bugs found!\n\n");
    }
    return 0;
}