HDU 1907&&2509

N堆取石子，取完最后者输。

有个叫SJ定理。

#include"iostream"
using namespace std;
int main()
{
	int t;
	cin>>t;
	while(t--)
	{
		int s[50],n;
		cin>>n;
		int i,flag=0,ans=0;
		for(i=0;i<n;i++)
		{
			cin>>s[i];
			ans^=s[i];
			if(s[i]>1)
				flag=1;
		}
		if(!flag)
		{
			if(n%2==0)
			cout<<"John"<<endl;
			else cout<<"Brother"<<endl;
			continue;
		}
		if(ans){
			cout<<"John"<<endl;
			continue;
		}
		cout<<"Brother"<<endl;

	}
	return 0;
}

2509

#include"iostream"
using namespace std;
int main()
{
	int t;
	
	while(cin>>t)
	{
		int s;		
		int i,flag=0,ans=0;
		for(i=0;i<t;i++)
		{
			cin>>s;
			ans^=s;
			if(s>1)
				flag=1;
		}
		if(!flag)
		{
			if(t%2==0)
			cout<<"Yes"<<endl;
			else cout<<"No"<<endl;
			continue;
		}
		if(ans){
			cout<<"Yes"<<endl;
			continue;
		}
		cout<<"No"<<endl;
	}
	
	return 0;
}