RhodeCode

      items[idx].next = items[rdx].next;

      items[items[rdx].next].prev = idx;

      items[rdx].next = idx;

      index.set(item, idx);

    }

    /// \brief Clears the union-find data structure

    ///

    /// Erase each item from the data structure.

    void clear() {

      items.clear();

      firstClass = firstFreeClass = firstFreeItem = -1;

    }

    /// \brief Gives back the class of the \e item.

    ///

    /// Gives back the class of the \e item.

    int find(const Item &item) const {

      return items[index[item]].cls;

    }

    /// \brief Gives back a representant item of the component.

    ///