87 lines
1.9 KiB
C++
87 lines
1.9 KiB
C++
#ifndef ITALIANO_H_
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#define ITALIANO_H_
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#include "algorithm/roditty_zwick.h"
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#include "algorithm/tarjan.h"
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#include "tree/breadth_first_tree.h"
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#include <forward_list>
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using namespace graph;
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using namespace tree;
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namespace algo {
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template<typename T>
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class Italiano : public RodittyZwick<T> {
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public:
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Italiano(Digraph<T> G) : G(G) {}
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void init();
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bool query(const T& u, const T& v);
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void remove(const T& u, const T& v);
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private:
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Digraph<T> G;
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// Connect each vertex with its representative SCC
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std::map<T, SCC<T>> TC;
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// Reachability trees
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std::map<T, std::set<T>> RT;
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// Incoming / Outgoing edges
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struct Edges {
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std::forward_list<T> Ein;
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std::forward_list<T> Eout;
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};
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std::map<SCC<T>, Edges> E;
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};
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template<typename T>
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void Italiano<T>::init() {
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}
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template<typename T>
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bool Italiano<T>::query(const T& u, const T& v) {
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return TC[u] == TC[v];
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}
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template<typename T>
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void Italiano<T>::remove(const T& u, const T& v) {
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for (const auto& w : G.adjMatrix) {
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// Check if (u,v) edge of T(w) || p(w,v) points to (u,v)
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// If yes => set p(w, v) to point to the next edge (u',v) in Ein(v)
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// If (u,v) the last edge, then set it to point to null
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// If T(w) contains u' then the new edge reconnects v to T(w)
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// As this needs to be checked, we set R(w) <- {v}
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// If (u,v) is not edge of T(w) or is the last edge in Ein(v), R(w) <- phi
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// Remove (u,v) from Eout(u) and Ein(v)
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}
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for (const auto& w : G.adjMatrix) {
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// Check tentative pointers of the vertices in R(w).
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// While there is a vertex x in R(w), scan the edges in Ein(x), starting
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// from the edge pointed to by p(w,x), until an edge (u',x) for which
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// p(w,u') != null is found or Ein(x) is exhausted.
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// If such edge is found, x is removed from R(w).
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// If the list is exhausted, set p(w,x) to null and M(w,x) to 0
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// Then scan all Eout(x). If (x,x') is tree edge, add x' to R(w)
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}
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}
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} // namespace algo
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#endif |