73 lines
1.9 KiB
C++
73 lines
1.9 KiB
C++
#ifndef KING_H_
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#define KING_H_
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#include "algorithm/dynamic_reachability.h"
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#include "algorithm/italiano.h"
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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 King : public DynamicReachability<T> {
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public:
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King() = default;
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King(Digraph<T> G) { this->G = G; }
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// Initialize decremental maintenance data structures for DAGs for each
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// vertex's in and out reachability trees
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void init() override;
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// Execute reachability query q(u, v) from vertex u to vertex v
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// in O(n) using the stored decremental maintenance data structure for DAGs
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bool query(const T& u, const T& v) override;
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// Delete edge e(u, v) from all reachability trees and update each one of
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// them using the decremental reachability algorithm for DAGs
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void remove(const T& u, const T& v) override;
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// Insert edge e(u, v) by reconstructing all reachability trees
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void insert(const T& u, const T& v) override;
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private:
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// Connect each reachabiliy tree with decremental maintenance data structure
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std::map<T, Italiano<T>> In;
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std::map<T, Italiano<T>> Out;
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};
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template<typename T>
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void King<T>::init() {
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for (const auto& u : this->G.vertices()) {
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In[u] = Italiano<T>(BreadthFirstTree<T>(this->G.reverse(), u));
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In[u].init();
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Out[u] = Italiano<T>(BreadthFirstTree<T>(this->G, u));
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Out[u].init();
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}
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}
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template<typename T>
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bool King<T>::query(const T& u, const T& v) {
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return std::any_of(this->G.vertices().begin(), this->G.vertices().end(),
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[&](const T& w) {
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return In[w].query(w, u) && Out[w].query(w, v);
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});
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}
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template<typename T>
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void King<T>::remove(const T& u, const T& v) {
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this->G.remove(u, v);
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for (const auto& w : this->G.vertices()) {
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In[w].remove(v, u);
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Out[w].remove(u, v);
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}
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}
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template<typename T>
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void King<T>::insert(const T& u, const T& v) {
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this->G.insert(u, v);
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init();
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}
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} // namespace algo
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#endif |