11063

This one is a shitty problem.

#include <iostream>
#include <cstdio>
#include <cstring>

using namespace std;

bool arr[20000+5];

int main()
{
	int n,a,kase=1;
	int prev=-1;
	int val[105];
	bool Bseq;
	while(scanf ("%d", &n) != EOF)
	{
		Bseq=1;
		for(int i=0;i<n;i++)
		{
			cin>>val[i];
		}
		for(int i=0;i<n-1;i++)
		{
			if(val[i]<1 || val[i]>=val[i+1])
			{
				Bseq=0;
				break;
			}
		}

		if(Bseq)
		{
			memset(arr,0,sizeof(arr));
			for(int i=0;i<n;i++)
			{
				for(int j=i;j<n;j++)
				{
					a=val[i]+val[j];
					if(arr[a])
					{
						Bseq=0;
						i=j=n;
					}
					else
					arr[a]=1;
				}
			}
			if(Bseq)
			cout<<"Case #"<<kase++<<": It is a B2-Sequence.\n\n";
			else
			cout<<"Case #"<<kase++<<": It is not a B2-Sequence.\n\n";
		}
		else
		cout<<"Case #"<<kase++<<": It is not a B2-Sequence.\n\n";
	}
}