inline void LibInsert(Position p) {
		//libs.insert(p);
		++numLibs;
		libSum+=p;
		libSumSq+=p*p;
	}
	inline void LibErase(Position p) {
		//libs.erase(p);
		--numLibs;
		libSum-=p;
		libSumSq-=p*p;
	}
	inline bool IsInAtari() {
		if(!numLibs)
			return 0;
		return libSum*libSum == numLibs*libSumSq;
	}