Method apply

pyvrp/cpp/search/Exchange.h:231–256

template <size_t N, size_t M>
void Exchange<N, M>::apply(Route::Node *U, Route::Node *V) const
{
    stats_.numApplications++;

    auto &uRoute = *U->route();
    auto &vRoute = *V->route();
    auto *uToInsert = N == 1 ? U : uRoute[U->idx() + N - 1];
    auto *insertUAfter = M == 0 ? V : vRoute[V->idx() + M - 1];

    // Insert these 'extra' nodes of U after the end of V...
    for (size_t count = 0; count != N - M; ++count)
    {
        auto *prev = p(uToInsert);
        uRoute.remove(uToInsert->idx());
        vRoute.insert(insertUAfter->idx() + 1, uToInsert);
        uToInsert = prev;
    }

    // ...and swap the overlapping nodes!
    for (size_t count = 0; count != M; ++count)
    {
        Route::swap(U, V);
        U = n(U);
        V = n(V);
    }
}
}  // namespace pyvrp::search

#endif  // PYVRP_SEARCH_EXCHANGE_H