线性基模板

存个板子

typedef long long ll;

struct base
{
    ll a[63];
    vector<ll> p;
    bool flag;//标记答案集合中是否有0
    base()
    {
        fill(a, a + 63, 0ll);
        flag = false;
    }

    void init()
    {
        fill(a, a + 63, 0ll);
        p.clear();
        flag = false;
    }

    bool insert(ll val)
    {
        ll t = 1ll << 62;
        for (int i = 62; ~i; --i)
        {
            if (val & t)
            {
                if (!a[i])
                {
                    a[i] = val;
                    return true;
                }
                val ^= a[i];
            }
            t >>= 1;
        }
        flag = true;//能到这里说明能异或出0
        return false;
    }

    ll query_max()
    {
        ll ans = 0;
        for (int i = 62; ~i; --i)
            if ((ans ^ a[i]) > ans)
                ans ^= a[i];
        return ans;
    }

    ll query_min()
    {
        for (int i = 0; i <= 62; ++i)
        {
            if (a[i])
                return a[i];
        }
        return 0;
    }

    void rebuild()
    {
        ll t;
        for (int i = 62; ~i; --i)
        {
            if (!a[i]) continue;
            t = 1ll << i - 1;
            for (int j = i - 1; ~j; --j, t >>= 1)
                if (a[i] & t)
                    a[i] ^= a[j];
        }

        for (int i = 0; i <= 62; ++i)
            if (a[i])
                p.push_back(a[i]);
    }

    ll kth(ll k)
    {
        if (flag) --k;//答案集合中有0
        ll ans = 0;
        if (k >= (1ll << p.size()))
            return -1;
        ll t = 1ll << 62;
        for (int i = 62; ~i; --i, t >>= 1)
            if (k & t)
                ans ^= p[i];
        return ans;
    }

    inline ll &operator[](int i)
    {
        return a[i];
    }

    base operator+(base &b) const
    {
        base ans = *this;
        for (int i = 0; i <= 62; ++i)
            if (b[i])
                ans.insert(b[i]);
        return ans;
    }
};