NonPlanarCore.h

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#pragma once
 
#include <ogdf/basic/CombinatorialEmbedding.h>
#include <ogdf/basic/Graph.h>
#include <ogdf/basic/GraphCopy.h>
#include <ogdf/basic/GraphList.h>
#include <ogdf/basic/List.h>
#include <ogdf/basic/Queue.h>
#include <ogdf/basic/SList.h>
#include <ogdf/basic/basic.h>
#include <ogdf/basic/extended_graph_alg.h>
#include <ogdf/basic/simple_graph_alg.h>
#include <ogdf/decomposition/SPQRTree.h>
#include <ogdf/decomposition/Skeleton.h>
#include <ogdf/decomposition/StaticSPQRTree.h>
#include <ogdf/graphalg/MinSTCutBFS.h>
#include <ogdf/graphalg/MinSTCutDijkstra.h>
 
#include <utility>
 
namespace ogdf {
template<typename TCost>
class MinSTCutModule;
 
 
template<typename TCost = int>
class NonPlanarCore {
    template<typename T>
    friend class GlueMap;
 
public:
    struct CutEdge {
        const edge e; 
        const bool dir; 
 
        CutEdge(edge paramEdge, bool directed) : e(paramEdge), dir(directed) {};
    };
 
    explicit NonPlanarCore(const Graph& G, bool nonPlanarityGuaranteed = false);
 
    NonPlanarCore(const Graph& G, const EdgeArray<TCost>& weight,
            bool nonPlanarityGuaranteed = false);
 
    NonPlanarCore(const Graph& G, const EdgeArray<TCost>& weight,
            MinSTCutModule<TCost>* minSTCutModule, bool nonPlanarityGuaranteed = false);
 
    const Graph& core() const { return m_graph; }
 
    const Graph& originalGraph() const { return *m_pOriginal; }
 
    node original(node v) const { return m_orig[v]; }
 
    List<edge> original(edge e) const {
        List<edge> res;
        if (isVirtual(e)) {
            EdgeArray<edge> origEdgesOfThisSTComponent(*mapE(e));
            for (edge eInCop : origEdgesOfThisSTComponent.graphOf()->edges) {
                if (origEdgesOfThisSTComponent[eInCop] != nullptr) {
                    res.pushBack(origEdgesOfThisSTComponent[eInCop]);
                }
            }
        } else {
            res.pushBack(realEdge(e));
        }
        return res;
    }
 
    bool isVirtual(edge e) const { return m_real[e] == nullptr; }
 
    edge realEdge(edge e) const { return m_real[e]; }
 
    const EdgeArray<TCost>& cost() const { return m_cost; }
 
    node tNode(edge e) const { return m_tNode[e]; }
 
    node sNode(edge e) const { return m_sNode[e]; }
 
    EdgeArray<edge>* mapE(edge e) const { return m_mapE[e]; }
 
    TCost cost(edge e) const { return m_cost[e]; }
 
    const List<CutEdge>& mincut(edge e) const { return m_mincut[e]; }
 
    // destructor
    virtual ~NonPlanarCore();
 
 
    void retransform(const GraphCopy& planarCore, GraphCopy& planarGraph, bool pCisPlanar = true);
 
protected:
    void call(const Graph& G, const EdgeArray<TCost>* weight, MinSTCutModule<TCost>* minSTCutModule,
            bool nonPlanarityGuaranteed);
 
    void getAllMultiedges(List<edge>& winningEdges, List<edge>& losingEdges);
 
    void traversingPath(const Skeleton& Sv, edge eS, List<CutEdge>& path, NodeArray<node>& mapV,
            edge coreEdge, const EdgeArray<TCost>* weight_src, MinSTCutModule<TCost>* minSTCutModule);
 
    void splitEdgeIntoSections(edge e, List<node>& splitdummies);
 
    void removeSplitdummies(List<node>& splitdummies);
 
    void normalizeCutEdgeDirection(edge coreEdge);
 
    void importEmbedding(edge e);
 
    void markCore(NodeArray<bool>& mark);
 
    void inflateCrossing(node v);
 
    void getMincut(edge e, List<edge>& cut);
 
    void glue(edge eWinner, edge eLoser);
 
    void glueMincuts(edge eWinner, edge eLoser);
 
    Graph m_graph;
 
    const Graph* m_pOriginal;
 
    const GraphCopy* m_planarCore;
 
    GraphCopy* m_endGraph;
 
    NodeArray<node> m_orig;
 
    EdgeArray<edge> m_real;
 
    EdgeArray<List<CutEdge>> m_mincut;
 
    EdgeArray<TCost> m_cost;
 
    StaticSPQRTree m_T;
 
    EdgeArray<NodeArray<node>*> m_mapV;
 
    EdgeArray<EdgeArray<edge>*> m_mapE;
 
    EdgeArray<Graph*> m_underlyingGraphs;
 
    EdgeArray<node> m_sNode;
 
    EdgeArray<node> m_tNode;
};
 
template<typename TCost>
class GlueMap {
public:
    GlueMap(edge eWinner, edge eLoser, NonPlanarCore<TCost>& npc);
 
    void mapLoserToNewWinnerEdge(edge eInLoser);
 
    void mapLoserToWinnerNode(node vInLoser, node vInWinner);
 
    void mapLoserToNewWinnerNode(node vInLoser);
 
    void reorder(node vLoser, bool sameDirection, bool isTNodeOfPNode);
 
    node getWinnerNodeOfLoserNode(node v) const { return m_mapV_l2w[v]; }
 
    const Graph& getLoserGraph() const { return *m_gLoser; }
 
protected:
    NonPlanarCore<TCost>& m_npc;
    const edge m_eWinner;
    const edge m_eLoser;
    Graph* m_gWinner;
    const Graph* m_gLoser;
    EdgeArray<edge>* m_mapEwinner;
    const EdgeArray<edge>* m_mapEloser;
    NodeArray<node>* m_mapVwinner;
    const NodeArray<node>* m_mapVloser;
    NodeArray<node> m_mapV_l2w;
    EdgeArray<edge> m_mapE_l2w;
};
 
template<typename TCost>
NonPlanarCore<TCost>::NonPlanarCore(const Graph& G, bool nonPlanarityGuaranteed)
    : m_pOriginal(&G)
    , m_orig(m_graph)
    , m_real(m_graph, nullptr)
    , m_mincut(m_graph)
    , m_cost(m_graph)
    , m_T(G)
    , m_mapV(m_graph, nullptr)
    , m_mapE(m_graph, nullptr)
    , m_underlyingGraphs(m_graph, nullptr)
    , m_sNode(m_graph)
    , m_tNode(m_graph) {
    MinSTCutBFS<TCost> minSTCutBFS;
    call(G, nullptr, &minSTCutBFS, nonPlanarityGuaranteed);
}
 
template<typename TCost>
NonPlanarCore<TCost>::NonPlanarCore(const Graph& G, const EdgeArray<TCost>& weight,
        MinSTCutModule<TCost>* minSTCutModule, bool nonPlanarityGuaranteed)
    : m_pOriginal(&G)
    , m_orig(m_graph)
    , m_real(m_graph, nullptr)
    , m_mincut(m_graph)
    , m_cost(m_graph)
    , m_T(G)
    , m_mapV(m_graph, nullptr)
    , m_mapE(m_graph, nullptr)
    , m_underlyingGraphs(m_graph, nullptr)
    , m_sNode(m_graph)
    , m_tNode(m_graph) {
    call(G, &weight, minSTCutModule, nonPlanarityGuaranteed);
}
 
template<typename TCost>
NonPlanarCore<TCost>::NonPlanarCore(const Graph& G, const EdgeArray<TCost>& weight,
        bool nonPlanarityGuaranteed)
    : m_pOriginal(&G)
    , m_orig(m_graph)
    , m_real(m_graph, nullptr)
    , m_mincut(m_graph)
    , m_cost(m_graph)
    , m_T(G)
    , m_mapV(m_graph, nullptr)
    , m_mapE(m_graph, nullptr)
    , m_underlyingGraphs(m_graph, nullptr)
    , m_sNode(m_graph)
    , m_tNode(m_graph) {
    MinSTCutDijkstra<TCost> minSTCutDijkstra;
    call(G, &weight, &minSTCutDijkstra, nonPlanarityGuaranteed);
}
 
template<typename TCost>
NonPlanarCore<TCost>::~NonPlanarCore() {
    for (auto pointer : m_mapE) {
        delete pointer;
    }
    for (auto pointer : m_mapV) {
        delete pointer;
    }
    for (auto pointer : m_underlyingGraphs) {
        delete pointer;
    }
}
 
template<typename TCost>
void NonPlanarCore<TCost>::call(const Graph& G, const EdgeArray<TCost>* weight,
        MinSTCutModule<TCost>* minSTCutModule, bool nonPlanarityGuaranteed) {
    if (!nonPlanarityGuaranteed && isPlanar(G)) {
        return;
    }
    OGDF_ASSERT(!isPlanar(G));
    OGDF_ASSERT(isBiconnected(G));
 
    // mark tree nodes in the core
    NodeArray<bool> mark;
    markCore(mark);
 
    NodeArray<node> map(G, nullptr);
    NodeArray<node> mapAux(G, nullptr);
    const Graph& tree = m_T.tree();
 
    for (node v : tree.nodes) {
        if (!mark[v]) {
            continue;
        }
 
        Skeleton& S = m_T.skeleton(v);
 
        for (edge e : S.getGraph().edges) {
            node src = S.original(e->source());
            node tgt = S.original(e->target());
 
            if (tgt == src) {
                continue;
            }
 
            if (map[src] == nullptr) {
                m_orig[map[src] = m_graph.newNode()] = S.original(e->source());
            }
 
            if (map[tgt] == nullptr) {
                m_orig[map[tgt] = m_graph.newNode()] = S.original(e->target());
            }
 
            if (S.isVirtual(e)) {
                node w = S.twinTreeNode(e);
 
                if (!mark[w]) {
                    // new virtual edge in core graph
                    edge lastCreatedEdge = m_graph.newEdge(map[src], map[tgt]);
                    m_real[lastCreatedEdge] = nullptr;
                    traversingPath(S, e, m_mincut[lastCreatedEdge], mapAux, lastCreatedEdge, weight,
                            minSTCutModule);
                }
            } else {
                // new real edge in core graph
                edge lastCreatedEdge = m_graph.newEdge(map[src], map[tgt]);
                m_real[lastCreatedEdge] = S.realEdge(e);
                traversingPath(S, e, m_mincut[lastCreatedEdge], mapAux, lastCreatedEdge, weight,
                        minSTCutModule);
            }
        }
    }
 
    if (weight != nullptr) {
        for (edge e : m_graph.edges) {
            TCost cost(0);
            for (auto cutEdge : m_mincut[e]) {
                cost += (*weight)[cutEdge.e];
            }
            m_cost[e] = cost;
        }
    } else {
        for (edge e : m_graph.edges) {
            m_cost[e] = m_mincut[e].size();
        }
    }
 
    List<node> allNodes;
    m_graph.allNodes(allNodes);
 
    // The while loop is used to eliminate multiedges from the core. We're pruning P-Nodes.
    List<edge> winningMultiEdges;
    List<edge> losingMultiEdges;
    getAllMultiedges(winningMultiEdges, losingMultiEdges);
    while (!winningMultiEdges.empty() && !losingMultiEdges.empty()) {
        edge winningMultiEdge = winningMultiEdges.popFrontRet();
        edge losingMultiEdge = losingMultiEdges.popFrontRet();
#ifdef OGDF_DEBUG
        int sizeOfWinCut = m_mincut[winningMultiEdge].size();
        int sizeOfLosCut = m_mincut[losingMultiEdge].size();
#endif
 
        glue(winningMultiEdge, losingMultiEdge);
        glueMincuts(winningMultiEdge, losingMultiEdge);
 
        OGDF_ASSERT(m_mincut[winningMultiEdge].size() == sizeOfWinCut + sizeOfLosCut);
        delete m_underlyingGraphs[losingMultiEdge];
        delete m_mapV[losingMultiEdge];
        delete m_mapE[losingMultiEdge];
        m_real[winningMultiEdge] = nullptr;
        m_real[losingMultiEdge] = nullptr;
        m_graph.delEdge(losingMultiEdge);
    }
    // The for loop is used to eliminate deg 2 nodes from the core. We're pruning S-Nodes.
    for (node v : allNodes) {
        if (v->degree() != 2) {
            continue;
        }
        edge outEdge = v->firstAdj()->theEdge();
        edge inEdge = v->lastAdj()->theEdge();
 
        if (m_cost[inEdge] > m_cost[outEdge]) {
            std::swap(inEdge, outEdge);
        }
        // We join the embeddings of the underlying embeddings/graphs of both edges
        // so that outEdge gets integrated into inEdge
        glue(inEdge, outEdge);
 
        m_real[inEdge] = nullptr;
        m_real[outEdge] = nullptr;
 
        adjEntry adjSource = inEdge->adjSource()->cyclicSucc();
        adjEntry adjTarget = (outEdge->target() == v ? outEdge->adjSource()->cyclicSucc()
                                                     : outEdge->adjTarget()->cyclicSucc());
        if (inEdge->target() != v) {
            adjSource = adjTarget;
            adjTarget = inEdge->adjTarget()->cyclicSucc();
        }
        m_graph.move(inEdge, adjSource, ogdf::Direction::before, adjTarget, ogdf::Direction::before);
        delete m_underlyingGraphs[outEdge];
        delete m_mapV[outEdge];
        delete m_mapE[outEdge];
        m_graph.delNode(v);
    }
 
 
    if (nonPlanarityGuaranteed) {
        OGDF_ASSERT(!isPlanar(m_graph));
    }
}
 
template<typename TCost>
void NonPlanarCore<TCost>::markCore(NodeArray<bool>& mark) {
    const Graph& tree = m_T.tree();
 
    // We mark every tree node that belongs to the core
    mark.init(tree, true); // start with all nodes and unmark planar leaves
    NodeArray<int> degree(tree);
 
    Queue<node> Q;
 
    for (node v : tree.nodes) {
        degree[v] = v->degree();
        if (degree[v] <= 1) { // also append deg-0 node (T has only one node)
            Q.append(v);
        }
    }
 
    while (!Q.empty()) {
        node v = Q.pop();
 
        // if v has a planar skeleton
        if (m_T.typeOf(v) != SPQRTree::NodeType::RNode || isPlanar(m_T.skeleton(v).getGraph())) {
            mark[v] = false; // unmark this leaf
 
            node w = nullptr;
            for (adjEntry adj : v->adjEntries) {
                node x = adj->twinNode();
                if (mark[x]) {
                    w = x;
                    break;
                }
            }
 
            if (w != nullptr) {
                --degree[w];
                if (degree[w] == 1) {
                    Q.append(w);
                }
            }
        }
    }
}
 
struct QueueEntry {
    QueueEntry(node p, node v) : m_parent(p), m_current(v) { }
 
    node m_parent;
    node m_current;
};
 
template<typename TCost>
void NonPlanarCore<TCost>::traversingPath(const Skeleton& Sv, edge eS, List<CutEdge>& path,
        NodeArray<node>& mapV, edge coreEdge, const EdgeArray<TCost>* weight_src,
        MinSTCutModule<TCost>* minSTCutModule) {
    List<CutEdge>& currPath = path;
 
    // Build the graph representing the planar st-component
    Graph* h_pointer = new Graph();
    Graph& H = *h_pointer;
 
    EdgeArray<edge>* mapE_src_pointer = new EdgeArray<edge>(H, nullptr);
    EdgeArray<edge>& mapE_src = *mapE_src_pointer;
    NodeArray<node>* mapV_src_pointer = new NodeArray<node>(H, nullptr);
    NodeArray<node>& mapV_src = *mapV_src_pointer;
    SListPure<node> nodes;
    SListPure<edge> multedges;
 
    if (Sv.isVirtual(eS)) {
        Queue<QueueEntry> Q;
        Q.append(QueueEntry(Sv.treeNode(), Sv.twinTreeNode(eS)));
 
        while (!Q.empty()) {
            QueueEntry x = Q.pop();
            node parent = x.m_parent;
            node current = x.m_current;
 
            const Skeleton& S = m_T.skeleton(current);
            for (edge e : S.getGraph().edges) {
                if (S.isVirtual(e)) {
                    continue;
                }
 
                node src = S.original(e->source());
                node tgt = S.original(e->target());
 
                if (mapV[src] == nullptr) {
                    nodes.pushBack(src);
                    mapV[src] = H.newNode();
                    mapV_src[mapV[src]] = src;
                }
                if (mapV[tgt] == nullptr) {
                    nodes.pushBack(tgt);
                    mapV[tgt] = H.newNode();
                    mapV_src[mapV[tgt]] = tgt;
                }
 
                edge e_new = H.newEdge(mapV[src], mapV[tgt]);
                mapE_src[e_new] = S.realEdge(e);
                OGDF_ASSERT(mapE_src[e_new]->source() != nullptr);
            }
 
            for (adjEntry adj : current->adjEntries) {
                node w = adj->twinNode();
                if (w != parent) {
                    Q.append(QueueEntry(current, w));
                }
            }
        }
    } else {
        nodes.pushBack(Sv.original(eS->source()));
        nodes.pushBack(Sv.original(eS->target()));
        mapV[Sv.original(eS->source())] = H.newNode();
        mapV_src[mapV[Sv.original(eS->source())]] = Sv.original(eS->source());
        mapV[Sv.original(eS->target())] = H.newNode();
        mapV_src[mapV[Sv.original(eS->target())]] = Sv.original(eS->target());
        mapE_src[H.newEdge(mapV[Sv.original(eS->source())], mapV[Sv.original(eS->target())])] =
                Sv.realEdge(eS);
    }
    // add st-edge
    edge e_st = H.newEdge(mapV[Sv.original(eS->source())], mapV[Sv.original(eS->target())]);
    m_sNode[coreEdge] = mapV[Sv.original(eS->source())];
    m_tNode[coreEdge] = mapV[Sv.original(eS->target())];
 
    // Compute planar embedding of H
#ifdef OGDF_DEBUG
    bool ok =
#endif
            planarEmbed(H);
    OGDF_ASSERT(ok);
    CombinatorialEmbedding E(H);
 
    // we rearange the adj Lists of s and t, so that adj(e_st) is the first adj
    List<adjEntry> adjListFront;
    List<adjEntry> adjListBack;
    e_st->source()->allAdjEntries(adjListFront);
    if (adjListFront.front() != e_st->adjSource()) {
        adjListFront.split(adjListFront.search(e_st->adjSource()), adjListFront, adjListBack);
        adjListFront.concFront(adjListBack);
        H.sort(e_st->source(), adjListFront);
    }
 
    e_st->target()->allAdjEntries(adjListFront);
    if (adjListFront.front() != e_st->adjTarget()) {
        adjListFront.split(adjListFront.search(e_st->adjTarget()), adjListFront, adjListBack,
                ogdf::Direction::before);
        adjListFront.concFront(adjListBack);
        H.sort(e_st->target(), adjListFront);
    }
 
    if (Sv.isVirtual(eS)) {
        List<edge> edgeList;
        if (weight_src != nullptr) {
            EdgeArray<TCost> weight(H);
            for (edge e : H.edges) {
                if (e != e_st) {
                    weight[e] = (*weight_src)[mapE_src[e]];
                }
            }
            minSTCutModule->call(H, weight, e_st->source(), e_st->target(), edgeList, e_st);
        } else {
            minSTCutModule->call(H, e_st->source(), e_st->target(), edgeList, e_st);
        }
        auto it = edgeList.begin();
        for (; it != edgeList.end(); it++) {
            currPath.pushBack(CutEdge(mapE_src[*it], minSTCutModule->direction(*it)));
        }
    } else {
        OGDF_ASSERT(Sv.realEdge(eS) != nullptr);
        currPath.pushFront(CutEdge(Sv.realEdge(eS), true));
    }
    H.delEdge(e_st);
 
    OGDF_ASSERT(m_underlyingGraphs[coreEdge] == nullptr);
    m_underlyingGraphs[coreEdge] = h_pointer;
    OGDF_ASSERT(m_mapE[coreEdge] == nullptr);
    m_mapE[coreEdge] = mapE_src_pointer;
    OGDF_ASSERT(m_mapV[coreEdge] == nullptr);
    m_mapV[coreEdge] = mapV_src_pointer;
#ifdef OGDF_DEBUG
    for (node v : H.nodes) {
        OGDF_ASSERT(mapV_src[v] != nullptr);
    }
    for (edge e : H.edges) {
        OGDF_ASSERT(mapE_src[e] != nullptr);
    }
#endif
 
    for (node v : nodes) {
        mapV[v] = nullptr;
    }
}
 
template<typename TCost>
void NonPlanarCore<TCost>::getAllMultiedges(List<edge>& winningEdges, List<edge>& losingEdges) {
    winningEdges.clear();
    losingEdges.clear();
    SListPure<edge> edges;
    EdgeArray<int> minIndex(m_graph), maxIndex(m_graph);
    parallelFreeSortUndirected(m_graph, edges, minIndex, maxIndex);
 
    SListConstIterator<edge> it = edges.begin();
    edge ePrev = *it, e;
    for (it = ++it; it.valid(); ++it, ePrev = e) {
        e = *it;
        if (minIndex[ePrev] == minIndex[e] && maxIndex[ePrev] == maxIndex[e]) {
            winningEdges.pushFront(ePrev);
            losingEdges.pushFront(e);
        }
    }
}
 
template<typename TCost>
void NonPlanarCore<TCost>::glue(edge eWinner, edge eLoser) {
    GlueMap<TCost> map(eWinner, eLoser, *this);
 
    // true iff this glueing is about a PNode (so a glueing at two common nodes)
    bool thisIsAboutAPNode = false;
    if (eLoser->isParallelUndirected(eWinner)) {
        thisIsAboutAPNode = true;
    }
 
    // find the s- and t-nodes in their skeleton for both of the edges
    node sWinner = m_sNode[eWinner];
    node tWinner = m_tNode[eWinner];
    node sLoser = m_sNode[eLoser];
    node tLoser = m_tNode[eLoser];
 
    bool sameDirection {!eWinner->isInvertedDirected(eLoser)};
 
    // we get a list of all nodes of the loser graph
    List<node> allNodesButSt;
    map.getLoserGraph().allNodes(allNodesButSt);
 
#ifdef OGDF_DEBUG
    bool ok = true;
#endif
 
    // for both s and t of eLoser we check if it's either the s or the t node of eWinner
    // if one of it is, we delete it from the list of nodes, that are to be added
    // otherwise it stays in 'allNodesButSt' to be added later
    if (eLoser->source() == eWinner->source() || eLoser->source() == eWinner->target()) {
#ifdef OGDF_DEBUG
        ok =
#endif
                allNodesButSt.removeFirst(sLoser);
        OGDF_ASSERT(ok);
        if (eLoser->source() == eWinner->source()) {
            map.mapLoserToWinnerNode(sLoser, sWinner);
        } else {
            map.mapLoserToWinnerNode(sLoser, tWinner);
        }
        OGDF_ASSERT(!allNodesButSt.search(sLoser).valid());
    }
    if (eLoser->target() == eWinner->source() || eLoser->target() == eWinner->target()) {
#ifdef OGDF_DEBUG
        ok =
#endif
                allNodesButSt.removeFirst(tLoser);
        OGDF_ASSERT(ok);
        if (eLoser->target() == eWinner->source()) {
            map.mapLoserToWinnerNode(tLoser, sWinner);
        } else {
            map.mapLoserToWinnerNode(tLoser, tWinner);
        }
        OGDF_ASSERT(!allNodesButSt.search(tLoser).valid());
    }
 
 
    // insert the remaining nodes of the loser graph into the winner graph
    for (node v : allNodesButSt) {
        map.mapLoserToNewWinnerNode(v);
    }
 
    // insert all edges of the loser graph into the the winner graph
    for (edge e : map.getLoserGraph().edges) {
        map.mapLoserToNewWinnerEdge(e);
    }
 
    // reorder the adjEntries of every node of the loser graph in the winner graph,
    // to match the embedding in the loser graph
    List<node> allNodes = allNodesButSt;
    allNodes.pushBack(sLoser);
    allNodes.pushBack(tLoser);
    for (node v : allNodes) {
        map.reorder(v, sameDirection, (tLoser == v && thisIsAboutAPNode));
    }
    if (!thisIsAboutAPNode) {
        if (eWinner->source() == eLoser->source()) {
            m_sNode[eWinner] = map.getWinnerNodeOfLoserNode(tLoser);
        }
        if (eWinner->target() == eLoser->source()) {
            m_tNode[eWinner] = map.getWinnerNodeOfLoserNode(tLoser);
        }
        if (eWinner->source() == eLoser->target()) {
            m_sNode[eWinner] = map.getWinnerNodeOfLoserNode(sLoser);
        }
        if (eWinner->target() == eLoser->target()) {
            m_tNode[eWinner] = map.getWinnerNodeOfLoserNode(sLoser);
        }
    }
}
 
template<typename TCost>
void NonPlanarCore<TCost>::retransform(const GraphCopy& planarCore, GraphCopy& planarGraph,
        bool pCisPlanar) {
#ifdef OGDF_DEBUG
    GraphCopy copyCore(planarCore);
    copyCore.removePseudoCrossings();
    OGDF_ASSERT(copyCore.numberOfNodes() == planarCore.numberOfNodes());
#endif
    m_endGraph = &planarGraph;
    m_planarCore = &planarCore;
    OGDF_ASSERT(!pCisPlanar || m_planarCore->genus() == 0);
    m_endGraph->clear();
    m_endGraph->setOriginalGraph(*m_pOriginal);
    List<node> allNodes;
    m_pOriginal->allNodes(allNodes);
    EdgeArray<edge> eCopy(*m_pOriginal, nullptr);
    NodeArray<node> nCopy(*m_pOriginal, nullptr);
    m_endGraph->insert(allNodes.begin(), allNodes.end(), filter_any_edge, nCopy, eCopy);
 
#ifdef OGDF_DEBUG
    for (node v : m_endGraph->nodes) {
        List<adjEntry> adjEntries;
        v->allAdjEntries(adjEntries);
        OGDF_ASSERT(v->degree() == adjEntries.size());
    }
#endif
 
    // For every node of the core we rearrange the adjacency order of the corresponding endGraph node
    // according to the planarized core.
    for (node v : m_planarCore->nodes) {
        if (m_planarCore->isDummy(v)) {
            continue;
        }
        List<adjEntry> pcOrder;
        v->allAdjEntries(pcOrder);
        List<adjEntry> newOrder;
        node coreNode = m_planarCore->original(v);
        OGDF_ASSERT(coreNode != nullptr);
        for (adjEntry adjPC : v->adjEntries) {
            edge coreEdge = m_planarCore->original(adjPC->theEdge());
            EdgeArray<edge>& mapE = *m_mapE[coreEdge];
            NodeArray<node>& mapV = *m_mapV[coreEdge];
            node stNode = (mapV[m_sNode[coreEdge]] == original(coreNode) ? m_sNode[coreEdge]
                                                                         : m_tNode[coreEdge]);
            // find the node of emb which represents the same node v represents
            for (adjEntry adjEmb : stNode->adjEntries) {
                if (adjEmb->theEdge()->source() == adjEmb->theNode()) {
                    newOrder.pushBack(m_endGraph->copy(mapE[adjEmb->theEdge()])->adjSource());
                } else {
                    newOrder.pushBack(m_endGraph->copy(mapE[adjEmb->theEdge()])->adjTarget());
                }
            }
        }
        m_endGraph->sort(m_endGraph->copy(original(coreNode)), newOrder);
    }
    if (!pCisPlanar) {
        for (edge e : m_graph.edges) {
            importEmbedding(e);
        }
        return;
    } else {
        List<node> splitdummies;
        for (edge e : m_graph.edges) {
            // for every edge from the core we ensure, that the embedding of the subgraph it describes
            // is the same in both the original and the end graph
            importEmbedding(e);
            // reverse all cut edges, which are not the same direction as e
            normalizeCutEdgeDirection(e);
            // to ensure the right order of the inserted crossings, we insert dummy nodes
            // to split the edge in sections, each of which only has one crossing
            splitEdgeIntoSections(e, splitdummies);
        }
 
        // now we can start and insert the crossings of the planar core into the end graph.
        // a node represents a crossing if it's a dummy
        for (node v : m_planarCore->nodes) {
            if (m_planarCore->isDummy(v)) {
                inflateCrossing(v);
            }
        }
        OGDF_ASSERT(m_endGraph->genus() == 0);
 
        removeSplitdummies(splitdummies);
        for (edge e : m_graph.edges) {
            normalizeCutEdgeDirection(e);
        }
    }
}
 
template<typename TCost>
void NonPlanarCore<TCost>::normalizeCutEdgeDirection(edge coreEdge) {
    for (auto cutE : m_mincut[coreEdge]) {
        if (!cutE.dir) {
            for (edge e : m_endGraph->chain(cutE.e)) {
                m_endGraph->reverseEdge(e);
            }
        }
    }
}
 
template<typename TCost>
void NonPlanarCore<TCost>::removeSplitdummies(List<node>& splitdummies) {
    for (node v : splitdummies) {
        edge eIn = v->firstAdj()->theEdge();
        edge eOut = v->lastAdj()->theEdge();
        if (eIn->target() == v) {
            m_endGraph->unsplit(eIn, eOut);
        } else {
            m_endGraph->unsplit(eOut, eIn);
        }
    }
}
 
template<typename TCost>
void NonPlanarCore<TCost>::splitEdgeIntoSections(edge e, List<node>& splitdummies) {
    List<edge> chain = m_planarCore->chain(e);
    int chainSize = chain.size();
    while (chainSize > 2) {
        for (CutEdge cutEdge : mincut(e)) {
            splitdummies.pushBack(m_endGraph->split(m_endGraph->copy(cutEdge.e))->source());
        }
        chainSize--;
    }
#ifdef OGDF_DEBUG
    for (CutEdge cutEdge : mincut(e)) {
        if (chain.size() < 3) {
            OGDF_ASSERT(m_endGraph->chain(cutEdge.e).size() == 1);
        } else {
            OGDF_ASSERT(m_endGraph->chain(cutEdge.e).size() == chain.size() - 1);
        }
        OGDF_ASSERT(m_endGraph->original(m_endGraph->chain(cutEdge.e).front()) == cutEdge.e);
    }
#endif
}
 
template<typename TCost>
void NonPlanarCore<TCost>::importEmbedding(edge e) {
    const Graph& embG = *m_underlyingGraphs[e];
    // a map from the nodes of the emb to those in the end graph
    const EdgeArray<edge>& mapE_toOrig = *m_mapE[e];
    // bc the edges of the end graph are split for the crossing insertion,
    // a map of the emb might have more than one edge in the endgraph, we just
    // map the AdjEntries of both source and target of each edge of emb
    // to AdjEntries in the end graph
    const NodeArray<node>& mapV_toOrig = *m_mapV[e];
    AdjEntryArray<adjEntry> mapA_toFinal(embG, nullptr);
    for (auto it = mapE_toOrig.begin(); it != mapE_toOrig.end(); it++) {
        OGDF_ASSERT(it.key() != nullptr);
        OGDF_ASSERT((*it) != nullptr);
        OGDF_ASSERT((*it)->graphOf() == m_pOriginal);
        mapA_toFinal[it.key()->adjSource()] = m_endGraph->chain(*it).front()->adjSource();
        mapA_toFinal[it.key()->adjTarget()] = m_endGraph->chain(*it).back()->adjTarget();
    }
    node s(m_sNode[e]), t(m_tNode[e]);
    List<node> nodesOfEmb;
    embG.allNodes(nodesOfEmb);
    // for every node of emb we order the adjEntries of the corresponding node
    // in the end graph, so that both match
    for (node v : nodesOfEmb) {
        if (v == s || v == t) {
            continue;
        }
        List<adjEntry> rightAdjOrder;
        for (adjEntry adj = v->firstAdj(); adj; adj = adj->succ()) {
            rightAdjOrder.pushBack(mapA_toFinal[adj]);
        }
        m_endGraph->sort(m_endGraph->copy(mapV_toOrig[v]), rightAdjOrder);
    }
}
 
template<typename TCost>
void NonPlanarCore<TCost>::inflateCrossing(node v) {
    // we want e1 and e2 to be these two edges
    //      ^
    //      |
    // e2-->v--->
    //      ^
    //      |
    //      e1
    edge e1 = v->firstAdj()->theEdge();
    while (e1->target() != v) {
        e1 = e1->adjSource()->succ()->theEdge();
    }
    edge e2 = e1->adjTarget()->succ()->theEdge();
    while (e2->target() != v) {
        e2 = e2->adjSource()->cyclicSucc()->theEdge();
    }
    if (e1 == e2->adjTarget()->cyclicSucc()->theEdge()) {
        edge help = e1;
        e1 = e2;
        e2 = help;
    }
    OGDF_ASSERT(e2 == e1->adjTarget()->cyclicSucc()->theEdge());
    List<edge> e1cut;
    getMincut(e1, e1cut);
    List<edge> e2cut;
    getMincut(e2, e2cut);
    OGDF_ASSERT(e1 != e2);
    OGDF_ASSERT(e1cut.size() > 0);
    OGDF_ASSERT(e2cut.size() > 0);
    // the actual crossing insertion
    // for (auto it1 = e1cut.begin(); it1.valid(); it1++)
    for (int i = 0; i < e1cut.size(); i++) {
        auto it1 = e1cut.get(i);
        edge crossingEdge = *it1;
        for (int j = 0; j < e2cut.size(); j++) {
            auto it2 = e2cut.get(j);
            edge crossedEdge = *it2;
            m_endGraph->insertCrossing(*it1, crossedEdge, true);
            OGDF_ASSERT(crossedEdge == *it2);
            e2cut.insertAfter(crossedEdge, it2);
            e2cut.del(it2);
        }
        OGDF_ASSERT(crossingEdge != *it1);
        e1cut.insertAfter(crossingEdge, it1);
        e1cut.del(it1);
    }
}
 
template<typename TCost>
void NonPlanarCore<TCost>::getMincut(edge e, List<edge>& cut) {
    OGDF_ASSERT(e->graphOf() == m_planarCore);
 
    cut.clear();
    // chain is a list of the edges of the planar core, that represent e
    List<edge> chain = m_planarCore->chain(m_planarCore->original(e));
    // this is the main part of this function:
    // as we know, the cut edges are split by splitdummies to partition the edge,
    // such that every crossing on the edge has its own section to be inserted into (denoted by pos)
    // cut_pre stores the first section for every cut edge
    for (CutEdge eCut : mincut(m_planarCore->original(e))) {
        OGDF_ASSERT(m_endGraph->chain(eCut.e).size() + 1 >= chain.size());
        // while iterating we have to differentiate between already inserted crossings and splitdummies
        // we can do that, by only counting the deg 2 nodes we pass while iterating through the chain of the cut edge
        auto it = m_endGraph->chain(eCut.e).begin();
        for (int i = 0; i < chain.pos(chain.search(e)); i++) {
            it++;
            while ((*it)->source()->degree() == 4) {
                it++;
                OGDF_ASSERT(it.valid());
            }
        }
        cut.pushBack(*(it));
    }
    // cut is the result of this function
}
 
template<typename TCost>
void NonPlanarCore<TCost>::glueMincuts(edge eWinner, edge eLoser) {
#ifdef OGDF_DEBUG
    if (eWinner->adjSource()->theNode() == eLoser->adjSource()->theNode()) {
        OGDF_ASSERT(eWinner->adjSource()->theNode() == eLoser->adjSource()->theNode());
        OGDF_ASSERT(eWinner->adjTarget()->theNode() == eLoser->adjTarget()->theNode());
    } else {
        OGDF_ASSERT(eWinner->adjSource()->theNode() == eLoser->adjTarget()->theNode());
        OGDF_ASSERT(eWinner->adjTarget()->theNode() == eLoser->adjSource()->theNode());
    }
#endif
    List<CutEdge> wincut = m_mincut[eWinner];
 
    List<CutEdge> losecut = m_mincut[eLoser];
 
    if (eWinner->source() == eLoser->target()) {
        List<CutEdge> newLosecut;
        for (auto cutEit = losecut.begin(); cutEit != losecut.end(); cutEit++) {
            newLosecut.pushBack(CutEdge((*cutEit).e, !(*cutEit).dir));
        }
        losecut = newLosecut;
    }
 
    wincut.conc(losecut);
    m_mincut[eWinner] = wincut;
    m_cost[eWinner] += m_cost[eLoser];
}
 
template<typename TCost>
GlueMap<TCost>::GlueMap(edge eWinner, edge eLoser, NonPlanarCore<TCost>& npc)
    : m_npc(npc), m_eWinner(eWinner), m_eLoser(eLoser) {
    OGDF_ASSERT(m_eWinner != m_eLoser);
 
    OGDF_ASSERT(m_npc.m_underlyingGraphs[m_eLoser] != nullptr);
    OGDF_ASSERT(m_npc.m_underlyingGraphs[m_eWinner] != nullptr);
 
    m_gLoser = m_npc.m_underlyingGraphs[m_eLoser];
    m_gWinner = m_npc.m_underlyingGraphs[m_eWinner];
 
    OGDF_ASSERT(m_gWinner != m_gLoser);
 
    OGDF_ASSERT(m_npc.m_mapV[m_eWinner] != nullptr);
    OGDF_ASSERT(m_npc.m_mapV[m_eLoser] != nullptr);
 
    m_mapVwinner = m_npc.m_mapV[m_eWinner];
    m_mapVloser = m_npc.m_mapV[m_eLoser];
 
    OGDF_ASSERT(m_npc.m_mapE[m_eWinner] != nullptr);
    OGDF_ASSERT(m_npc.m_mapE[m_eLoser] != nullptr);
 
    m_mapEwinner = m_npc.m_mapE[m_eWinner];
    m_mapEloser = m_npc.m_mapE[m_eLoser];
 
    OGDF_ASSERT(m_mapEloser->graphOf() == m_gLoser);
    OGDF_ASSERT(m_mapVloser->graphOf() == m_gLoser);
 
    OGDF_ASSERT(m_mapEwinner->graphOf() == m_gWinner);
    OGDF_ASSERT(m_mapVwinner->graphOf() == m_gWinner);
 
    m_mapE_l2w = EdgeArray<edge>(*m_gLoser, nullptr);
    m_mapV_l2w = NodeArray<node>(*m_gLoser, nullptr);
}
 
template<typename TCost>
void GlueMap<TCost>::mapLoserToNewWinnerEdge(edge loser) {
    edge newEdge = m_gWinner->newEdge(m_mapV_l2w[loser->source()], m_mapV_l2w[loser->target()]);
    m_mapE_l2w[loser] = newEdge;
    (*m_mapEwinner)[newEdge] = (*m_mapEloser)[loser];
}
 
template<typename TCost>
void GlueMap<TCost>::mapLoserToWinnerNode(node loser, node winner) {
    m_mapV_l2w[loser] = winner;
    (*m_mapVwinner)[winner] = (*m_mapVloser)[loser];
}
 
template<typename TCost>
void GlueMap<TCost>::mapLoserToNewWinnerNode(node loser) {
    node newNode = m_gWinner->newNode();
    m_mapV_l2w[loser] = newNode;
    (*m_mapVwinner)[newNode] = (*m_mapVloser)[loser];
}
 
template<typename TCost>
void GlueMap<TCost>::reorder(node vLoser, bool sameDirection, bool isTNodeOfPNode) {
    node vWinner = m_mapV_l2w[vLoser];
    List<adjEntry> rightAdjOrder;
    List<adjEntry> wrongAdjOrder;
    vWinner->allAdjEntries(wrongAdjOrder);
    OGDF_ASSERT(wrongAdjOrder.size() == vWinner->degree());
 
    OGDF_ASSERT(vLoser->degree() <= vWinner->degree());
    // for every adjEntry of v in the "right" graph (the embedding which we want to get into the "wrong" graph)
    // we search for the corresponding adjEntry in the list of adjEntries of the "wrong" v
    for (adjEntry adj : vLoser->adjEntries) {
        OGDF_ASSERT(m_mapE_l2w[adj->theEdge()] != nullptr);
        edge edgeInWinner = m_mapE_l2w[adj->theEdge()];
        adjEntry adj_in = (adj->theEdge()->adjSource() == adj ? edgeInWinner->adjSource()
                                                              : edgeInWinner->adjTarget());
        rightAdjOrder.pushBack(adj_in);
    }
    List<adjEntry> adjOrder;
    vWinner->allAdjEntries(adjOrder);
    OGDF_ASSERT(vLoser->degree() <= adjOrder.size());
    if (!sameDirection) {
        rightAdjOrder.reverse();
    }
    if (adjOrder.size() == rightAdjOrder.size()) {
        adjOrder = rightAdjOrder;
    } else {
        List<adjEntry> helpList;
        adjOrder.split(adjOrder.get(adjOrder.size() - rightAdjOrder.size()), adjOrder, helpList);
        if (isTNodeOfPNode) {
            adjOrder.concFront(rightAdjOrder);
        } else {
            adjOrder.conc(rightAdjOrder);
        }
    }
    m_gWinner->sort(vWinner, adjOrder);
}
}