pctree.cpp

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#include <ogdf/basic/Graph.h>
#include <ogdf/basic/pctree/PCTree.h>
#include <ogdf/fileformats/GraphIO.h>
#include <ogdf/tree/RadialTreeLayout.h>
 
using namespace ogdf;
using namespace pc_tree;
 
int main() {
    // create a tree with a given number of leaves
    std::vector<PCNode*> leaves;
    PCTree tree(7, &leaves);
 
    // the tree allows any order of its leaves
    OGDF_ASSERT(tree.isTrivial());
    OGDF_ASSERT(tree.getLeafCount() == 7);
    OGDF_ASSERT(tree.getPNodeCount() == 1);
    OGDF_ASSERT(tree.getCNodeCount() == 0);
    OGDF_ASSERT(tree.possibleOrders<int>() == factorial(6));
    OGDF_ASSERT(tree.uniqueID(uid_utils::nodeToPosition) == "7:(6, 5, 4, 3, 2, 1, 0)");
 
    // now we can force some leaves to be consecutive in all represented orders
    tree.makeConsecutive({leaves.at(3), leaves.at(4), leaves.at(5)});
    OGDF_ASSERT(tree.uniqueID(uid_utils::nodeToPosition) == "8:(7:(5, 4, 3), 6, 2, 1, 0)");
    OGDF_ASSERT(tree.getPNodeCount() == 2);
    OGDF_ASSERT(tree.possibleOrders<int>() == factorial(3) * factorial(4));
 
    // further updates further change the tree
    tree.makeConsecutive({leaves.at(4), leaves.at(5)});
    OGDF_ASSERT(tree.uniqueID(uid_utils::nodeToPosition) == "9:(8:[7:[5, 4], 3], 6, 2, 1, 0)");
 
    tree.makeConsecutive({leaves.at(0), leaves.at(1)});
    OGDF_ASSERT(tree.uniqueID(uid_utils::nodeToPosition) == "10:(9:[8:[5, 4], 3], 7:[1, 0], 6, 2)");
 
    tree.makeConsecutive({leaves.at(1), leaves.at(2)});
    OGDF_ASSERT(tree.uniqueID(uid_utils::nodeToPosition) == "10:[9:[8:[5, 4], 3], 7:[2, 1, 0], 6]");
 
    tree.makeConsecutive({leaves.at(2), leaves.at(3), leaves.at(4), leaves.at(5)});
    OGDF_ASSERT(tree.uniqueID(uid_utils::nodeToPosition) == "9:[6, 8:[7:[5, 4], 3], 2, 1, 0]");
 
    // if some leaves cannot be made consecutive, the update returns false and leaves the tree unchanged
    OGDF_ASSERT(tree.makeConsecutive({leaves.at(2), leaves.at(0)}) == false);
    OGDF_ASSERT(tree.uniqueID(uid_utils::nodeToPosition) == "9:[6, 8:[7:[5, 4], 3], 2, 1, 0]");
    OGDF_ASSERT(tree.possibleOrders<int>() == 8);
 
    // we can query the (arbitrary) current order of leaves and check whether any order is represented by the tree
    std::vector<PCNode*> currentLeafOrder =
            tree.currentLeafOrder(); // same entries as `leaves`, different order
    OGDF_ASSERT(tree.isValidOrder(currentLeafOrder));
    // use tree.getLeaves() to get the leaves in creation order
 
    // iterator for all inner nodes
    auto innerNode_it = tree.innerNodes();
    std::vector<PCNode*> innerNodes {innerNode_it.begin(), innerNode_it.end()};
    OGDF_ASSERT(innerNodes.size() == tree.getPNodeCount() + tree.getCNodeCount());
    OGDF_ASSERT(innerNodes.front() == tree.getRootNode());
 
    // we can also manually walk the tree
    PCNode* root = tree.getRootNode();
    OGDF_ASSERT(root->getChildCount() == 5); // 6, 8:[...], 2, 1, 0
    OGDF_ASSERT(root->getChild1()->isLeaf());
    for (PCNode* n : root->children()) {
        std::cout << n->index() << " ";
    }
    std::cout << std::endl;
 
    // we can visualize the PCTree
    ogdf::Graph G;
    ogdf::GraphAttributes GA(G);
    PCTreeNodeArray<ogdf::node> pc_repr(tree);
    tree.getTree(G, &GA, pc_repr);
    RadialTreeLayout l;
    l.rootSelection(RadialTreeLayout::RootSelectionType::Source);
    l.call(GA);
    GraphIO::write(GA, "pctree.svg");
 
    // PCTrees can also be reconstructed from strings
    PCTree from_string {"9:[6, 8:[7:[5, 4], 3], 2, 1, 0]", true};
    OGDF_ASSERT(from_string.getLeafCount() == tree.getLeafCount());
    OGDF_ASSERT(from_string.possibleOrders<int>() == tree.possibleOrders<int>());
    OGDF_ASSERT(from_string.uniqueID(uid_utils::nodeToPosition) == "9:[6, 8:[7:[5, 4], 3], 2, 1, 0]");
    // tree.getRestrictions() yields a list of updated via which the tree can also be reconstructed
 
    // alternatively, they can also be constructed manually
    PCTree manual;
    auto nr = manual.newNode(pc_tree::PCNodeType::CNode);
    auto n1 = manual.newNode(pc_tree::PCNodeType::PNode, nr);
    manual.insertLeaves(3, nr);
    auto n2 = manual.newNode(pc_tree::PCNodeType::PNode, nr);
    manual.insertLeaves(3, n2);
    manual.insertLeaves(3, nr);
    manual.insertLeaves(3, n1);
    std::stringstream ss;
    ss << manual;
    OGDF_ASSERT(ss.str() == "0:[11, 10, 9, 5:(8, 7, 6), 4, 3, 2, 1:(14, 13, 12)]");
 
    return 0;
}