B - 简单带权并查集 POJ - 2492 A Bug's Life

最新推荐文章于 2023-08-03 20:43:59 发布

转载最新推荐文章于 2023-08-03 20:43:59 发布 · 121 阅读

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原文链接：http://www.cnblogs.com/107acm/p/9429307.html

本文针对POJ-2492虫子交互问题进行了解析，通过并查集算法判断给定虫子交互列表是否符合仅有异性的假设条件。输入包括实验场景数量、每场实验中的虫子数及交互对，输出显示是否存在不符合假设的交互。

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POJ - 2492 http://poj.org/problem?id=2492

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.
InputThe 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.OutputThe 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.

题意是有n只虫，m对（异性），给出m对，问有没有错误的（不能出现同性）

种类并查集，画个表就知道关系转换了

#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <queue>
#include <map>
#include <set>
#include <stack>
#include <vector>
#define Twhile() int T;scanf("%d",&T);while(T--)
#define fora(i,a,b) for(i=a;i<b;i++)
#define fors(i,a,b) for(i=a;i>b;i--)
#define fora2(i,a,b) for(i=a;i<=b;i++)
#define fors2(i,a,b) for(i=a;i>=b;i--)
#define PI acos(-1.0)
#define eps 1e-6
#define INF 0x3f3f3f3f

typedef long long LL;
typedef long long LD;
using namespace std;
const int maxn=30000+11;
int fa[maxn],ran[maxn];//0:同1：异
int n,m,flag;
void init()
{
    flag=1;
    int i;
    fora2(i,0,n)
    {
        fa[i]=i;
        ran[i]=0;
    }
}
int findx(int x)
{
    if(x==fa[x])return x;
    int fx=findx(fa[x]);
    ran[x]=ran[x]^ran[fa[x]];
    return fa[x]=fx;
}
void solve(int x,int y)
{
    int fx=findx(x),fy=findx(y);
    if(fx!=fy)
    {
        ran[fy]=!(ran[y]^ran[x]);
        fa[fy]=fx;
    }
    else
    {
        int t=ran[x]^ran[y];
        flag=t;
    }
}
int main()
{
    int t=0;
    Twhile()
    {
        scanf("%d%d",&n,&m);
        init();
        while(m--)
        {
            int x,y;
            scanf("%d%d",&x,&y);
            if(flag)solve(x,y);
        }
        printf("Scenario #%d:\n",++t);
        if(flag)printf("No suspicious bugs found!\n");
        else
            printf("Suspicious bugs found!\n");
        
    }
    return 0;
}

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.

InputThe 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.OutputThe 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

Sample Output

Scenario #1:
Suspicious bugs found!

Scenario #2:
No suspicious bugs found!

Hint

Huge input,scanf is recommended.

转载于:https://www.cnblogs.com/107acm/p/9429307.html