关于正确性及效率求问

typedef unsigned long long ull;
constexpr int len=(1<<23);
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
struct HashMap {
	inline ull F(ull x) {
		static const ull s1=rng(),s2=rng(),s3=rng();
		x+=s1;
		x=(x^(x>>33))*s2;
		x=(x^(x>>30))*s3;
		return x;
	}
	bitset<len+5>hav;
	ull key[len+5];
	ull value[len+5];
	int gt(const ull&x) {
		int i=F(x)&(len-1);
		while(hav[i]&&key[i]!=x)i=(i+1)&(len-1);
		hav[i]=1,key[i]=x;
		return i;
	}
	ull& operator[](const ull&x) {
		return value[gt(x)];
	}
};

static const ull s1=rng(),s2=rng(),s3=rng();

ull s1=rng(),s2=rng(),s3=rng();

// static const ull s1=rng(),s2=rng(),s3=rng();
// cout<<x<<" "<<res[x]<<"->"<<y<<endl;

0 0->4
0 4->998244353
1000000000000000000 0->20120712
1000000000000000000 20120712->1000000000000000000
1000000000000000000 1000000000000000000->998244353
5000000000080482856

// ull s1=rng(),s2=rng(),s3=rng();
// cout<<x<<" "<<res[x]<<"->"<<y<<endl;

0 0->4
0 0->998244353
1000000000000000000 0->20120712
1000000000000000000 0->1000000000000000000
1000000000000000000 0->998244353
0