96 lines
2.2 KiB
C++
96 lines
2.2 KiB
C++
#ifndef FRIGIONI_H_
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#define FRIGIONI_H_
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#include "algorithm/decremental_reachability.h"
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#include "algorithm/roditty_zwick.h"
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#include <utility>
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using namespace graph;
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namespace algo {
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template<typename T>
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class Frigioni : public DecrementalReachability<T> {
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public:
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Frigioni() = default;
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Frigioni(Digraph<T> G) { this->G = G; }
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//
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void init() override;
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//
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bool query(const T& u, const T& v) override;
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//
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void remove(const T& u, const T& v) override;
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private:
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// Transitive closure matrix, used to answer reachability queries in O(1)
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std::map<T, std::map<T, bool>> TC;
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// Connect each vertex with its representative SCC
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std::map<T, SCC<T>> C;
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// Each scc's representative vertex reachability tree
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std::map<T, BreadthFirstTree<T>> RT;
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// Incoming / Outgoing / Internal edges of each SCC
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// Maps each SCC representative with struct Edges
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struct Edges {
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std::set<std::pair<T, T>> in;
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std::set<std::pair<T, T>> inc;
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std::set<std::pair<T, T>> out;
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};
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std::map<T, Edges> E;
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// Decremental maintenance of strongly connected components
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RodittyZwick<T> decremental;
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};
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template<typename T>
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void Frigioni<T>::init() {
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auto SCCs = Tarjan<T>(this->G.adjMatrix).execute();
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decremental = RodittyZwick<T>(this->G);
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decremental.init();
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for (auto& scc : SCCs) {
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RT[scc.id] = BreadthFirstTree<T>(this->G, scc.id);
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for (const auto& u : this->G.vertices()) {
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for (const auto& v : this->G.adjMatrix[u]) {
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TC[u][v] = false;
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if (scc.member(u)) {
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if (scc.member(v))
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E[scc.id].in.insert(std::make_pair(u, v));
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else
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E[scc.id].out.insert(std::make_pair(u, v));
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} else if (scc.member(v)) {
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E[scc.id].inc.insert(std::make_pair(u, v));
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}
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}
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}
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}
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for (auto& scc : SCCs) {
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for (const auto& u : this->G.vertices()) {
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if (scc.member(u)) {
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for (const auto& v : RT[scc.id].vertices()) {
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TC[u][v] = true;
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}
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}
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}
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}
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}
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template<typename T>
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bool Frigioni<T>::query(const T& u, const T& v) {
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return TC[u][v];
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}
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template<typename T>
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void Frigioni<T>::remove(const T& u, const T& v) {
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}
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} // namespace algo
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#endif |