hdu 1829-BFS二分图染色-输出真坑！！！！！！！！！！！！！！

本文描述了一个关于虫子互动的问题，通过图论的方法判断虫子是否仅与异性互动。使用了BFS算法来验证这一假设，并给出了具体的实现代码。

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A Bug's Life

Time Limit: 15000/5000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 18137 Accepted Submission(s): 5782

Problem 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.

Source

TUD Programming Contest 2005, Darmstadt, Germany

#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<queue>
#include<stack>
#include<vector>

using namespace std;

vector<int> map[3000];
int color[3000],n,row,flag,from,to,vis[3000];
 
void init()
{
	flag = 0; 
	memset(color,-1,sizeof(color));
	memset(vis,0,sizeof(vis));//BFS少不了标记
	for(int i = 1; i <= n; i++)
		map[i].clear();	
	while(row--)//构建图 
	{
		scanf("%d%d",&from,&to);
		map[from].push_back(to);//注意无向图
		map[to].push_back(from);
	}
}

bool BFS(int s)
{
	color[s] = 1;
	queue<int> q;
	q.push(s);
	while(!q.empty())
	{
		int temp = q.front();
		q.pop();
		if(!vis[temp])
		{
			for(int  i = 0; i < map[temp].size(); i++)
			{ 
				q.push(map[temp][i]);
				if(color[ map[temp][i] ] == -1)
					color[ map[temp][i] ] = color[temp] == 1?0:1;
				else 
				{
					if(color[ map[temp][i] ] == color[temp])
						return false;
					else 
						continue;
				}	
				
			}
			vis[temp] = 1;
		} 
	}
	return true;
}

int main()
{
	int t;
	scanf("%d",&t);
	for(int count = 1; count <= t; count++)
	{
		scanf("%d%d",&n,&row);//n为虫子的数目，row为接下来有row对虫子相互喜欢 
		init();
		printf("Scenario #%d:\n",count);
		for(int i = 1; i <= n; i++)//开始，每一个虫子都属于自己的集合 
		{
			if(!vis[i])
			{
				if(!BFS(i))
				{
					flag = 1;
					break;
				}
			}
		}
		if(!flag)
			printf("No suspicious bugs found!\n\n");//注意两个换行
		else 
			printf("Suspicious bugs found!\n\n");//我想知道为什么我复制粘贴粘贴过来的时候，S从大写变成了小写，害我找了两天的bug，mmp
	} 
	return 0;
}