hdu 1689 Alien’s Necklace

输出节点数为奇数且最小环的节点数

开始开2维数组果断超内存，看了别人的代码才知道用奇偶性来标记

#include<iostream>
#include<vector>
#include<queue>
#include<cstring>
#define maxn 10000+1
using namespace std;
vector<int>mapp[maxn];
int n,m;
int visit[maxn][2];
struct stu
{
	int pre;
	int now;
	int deep;
};
int bfs(int p)
{
	queue<stu>root;
	stu x,y;
	x.pre=-1;
	x.now=p;
	x.deep=0;
	root.push(x);
	while(root.size())
	{
		x=root.front();
		root.pop();
		if(x.now==p&&x.deep>=3&&x.deep%2) return x.deep;
		else if(x.now==p&&x.deep!=0) continue;
		for(int i=0;i<mapp[x.now].size();i++)
		{
			if(mapp[x.now][i]!=x.pre&&!visit[mapp[x.now][i]][(x.deep+1)%2])
			{
				y.pre=x.now;
				y.now=mapp[x.now][i];
				y.deep=x.deep+1;
				visit[y.now][y.deep%2]=1;
				root.push(y);
			}
		}
	}
	return 1<<30;
}
int main()
{
	cin.sync_with_stdio(false);
	int t;
	cin>>t;
	int casee=1;
	while(t--)
	{
		cin>>n>>m;
		for(int i=1;i<=n;i++)  mapp[i].clear();
		for(int i=0;i<m;i++)
		{
			int x,y;
			cin>>x>>y;
			mapp[x].push_back(y);
			mapp[y].push_back(x);
		}
		int ans=1<<30;
		for(int i=1;i<=n;i++)
		{
			memset(visit,0,sizeof(visit));
			ans=min(ans,bfs(i));
		}
		cout<<"Case "<<casee++<<": ";
		if(ans!=1<<30) cout<<"JYY has to use "<<ans<<" balls."<<endl;
		else cout<<"Poor JYY."<<endl;
	}
	return 0;
}