74 lines
2.0 KiB
C++
74 lines
2.0 KiB
C++
#ifndef DIJKSTRANODE_H
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#define DIJKSTRANODE_H
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/**
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* wrapper around a user data structure
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* adds additional fields needed for dijkstra calculation
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*/
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template <typename T> struct DijkstraNode {
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/** pos infinity */
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static constexpr float INF = +99999999;
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/** the user-element this node describes */
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const T* element;
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/** the previous dijkstra node (navigation path) */
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DijkstraNode<T>* previous;
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/** the weight from the start up to this element */
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float cumWeight;
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/** whether we already enqueued this node into the processing list (do NOT examing nodes twice) */
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bool enqueued;
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/** ctor */
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DijkstraNode(const T* element) : element(element), previous(), cumWeight(INF), enqueued(false) {;}
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};
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/**
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* data structure describing the connection between two nodes.
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* NOTE: only used to track already processed connections!
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*/
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template <typename T> struct DijkstraEdge {
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/** the edge's source */
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const DijkstraNode<T>* src;
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/** the edge's destination */
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const DijkstraNode<T>* dst;
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/** ctor */
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DijkstraEdge(const DijkstraNode<T>* src, const DijkstraNode<T>* dst) : src(src), dst(dst) {;}
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/** equal? (bi-directional! edge direction does NOT matter) */
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bool operator == (const DijkstraEdge& other) const {
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return ((dst == other.dst) && (src == other.src)) ||
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((src == other.dst) && (dst == other.src));
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}
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// std::set was slower than std::unordered_set
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// bool operator < (const DijkstraEdge& other) const {
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// return ((size_t)src * (size_t)dst) < ((size_t)other.src * (size_t)other.dst);
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// }
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};
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/** allows adding DijkstraEdge<T> to hash-maps */
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namespace std {
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template <typename T> struct hash<DijkstraEdge<T>>{
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size_t operator()(const DijkstraEdge<T>& e) const {
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// dunno why but this one provided the fastet results even though
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// this should lead to the most hash-collissions?!
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return hash<size_t>()( std::min((size_t)e.src, (size_t)e.dst) );
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//return hash<size_t>()( (size_t)e.src * (size_t)e.dst );
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}
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};
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}
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#endif // DIJKSTRANODE_H
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