!hash-set (slow, stupid)

typedef unsigned long long integer;

struct my_hash_map
{
    vector<integer> q;
    vector<char> used;
    int cnt;

    my_hash_map(int sz = 1)
    {
        q.assign(sz, 0);
        used.assign(sz, 0);
        cnt = 0;
    }

    void rehash(int sz)
    {
        if (sz <= sz(q))
            return;
        vector<integer> q_(sz, 0);
        vector<char> used_(sz, 0);
        for (int i = 0; i < sz(q); i++)
            if (used[i])
            {
                int pos = q[i] % (integer)sz;
                while (used_[pos])
                    pos = (pos + 1 == sz ? 0 : pos + 1);
                used_[pos] = 1;
                q_[pos] = q[i];
            }
        swap(q, q_);
        swap(used, used_);
    }

    void insert(integer val)
    {
        int pos = val % (integer)sz(q);
        while (used[pos])
        {
            if (q[pos] == val)
                return;
            pos = (pos + 1 == sz(q) ? 0 : pos + 1);
        }
        used[pos] = 1;
        q[pos] = val;
        cnt++;
        if (cnt * 2 > sz(q))
            rehash(2 * sz(q) + 3); // random (lol)
    }

    void erase(integer val)
    {
        int pos = val % (integer)sz(q);
        while (used[pos])
        {
            if (q[pos] == val)
            {
                cnt--;
                used[pos] = 0;
                return;
            }
            pos = (pos + 1 == sz(q) ? 0 : pos + 1);
        }
        return;
    }

    int count(integer val)
    {
        int pos = val % (integer)sz(q);
        while (used[pos])
        {
            if (q[pos] == val)
                return 1;
            pos = (pos + 1 == sz(q) ? 0 : pos + 1);
        }
        return 0;
    }
};