cp-templates/trees/segtreed.cc

template<typename T> class segtreed {
private:
    using size_type = uint64_t;
    size_type cnt, root;
    T _max;
    vector<T> d, b;
    vector<size_type> ls, rs;

    void _update(size_type s, size_type t, size_type &p, size_type l, size_type r, T c) {
        if (!p) p = ++cnt;
        if (l <= s && t <= r) {
            d[p] += c * (t - s + 1);
            b[p] += c;
            return;
        }
        size_type m = s + (t - s >> 1);
        if (!ls[p]) ls[p] = ++cnt;
        if (!rs[p]) rs[p] = ++cnt;
        if (b[p] && s != t) {
            d[ls[p]] += b[p] * (m - s + 1), d[rs[p]] += b[p] * (t - m);
            b[ls[p]] += b[p], b[rs[p]] += b[p];
            b[p] = 0;
        }
        if (l <= m) _update(s, m, ls[p], l, r, c);
        if (r > m)  _update(m + 1, t, rs[p], l, r, c);
        d[p] = d[ls[p]] + d[rs[p]];
    }

    T _query(size_type s, size_type t, size_type p, size_type l, size_type r) {
        if (!p) return {};
        if (l <= s && t <= r) return d[p];
        size_type m = s + (t - s >> 1);
        T res = {};
        if (b[p]) {
            d[ls[p]] += b[p] * (m - s + 1), d[rs[p]] += b[p] * (t - m);
            b[ls[p]] += b[p], b[rs[p]] += b[p];
            b[p] = 0;
        }
        if (l <= m) res += _query(s, m, ls[p], l, r);
        if (r > m)  res += _query(m + 1, t, rs[p], l, r);
        return res;
    }
public:
    segtreed(size_type n, T _max) : cnt(0), root(0), d(4 * n, {}), b(4 * n, {}), ls(4 * n, 0), rs(4 * n, 0), _max(_max) {}

    void update(size_type l, size_type r, T c) {
        _update({}, _max, root, l, r, c);
    }

    T query(size_type l, size_type r) {
        return _query({}, _max, root, l, r);
    }
};