50 lines
1.5 KiB
C++
50 lines
1.5 KiB
C++
#ifndef __CXXMPH_TRIGRAPH_H__
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#define __CXXMPH_TRIGRAPH_H__
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// Build a trigraph using a memory efficient representation.
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//
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// Prior knowledge of the number of edges and vertices for the graph is
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// required. For each vertex, we store how many edges touch it (degree) and the
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// index of the first edge in the vector of triples representing the edges.
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#include <stdint.h> // for uint32_t and friends
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#include <vector>
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namespace cxxmph {
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class TriGraph {
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public:
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struct Edge {
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Edge() { }
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Edge(uint32_t v0, uint32_t v1, uint32_t v2) {
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vertices[0] = v0;
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vertices[1] = v1;
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vertices[2] = v2;
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}
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uint32_t& operator[](uint8_t v) { return vertices[v]; }
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const uint32_t& operator[](uint8_t v) const { return vertices[v]; }
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uint32_t vertices[3];
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};
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TriGraph(uint32_t nedges, uint32_t nvertices);
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~TriGraph();
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void AddEdge(const Edge& edge);
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void RemoveEdge(uint32_t edge_id);
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void ExtractEdgesAndClear(std::vector<Edge>* edges);
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void DebugGraph() const;
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const std::vector<Edge>& edges() const { return edges_; }
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const std::vector<uint8_t>& vertex_degree() const { return vertex_degree_; }
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const std::vector<uint32_t>& first_edge() const { return first_edge_; }
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private:
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uint32_t nedges_; // total number of edges
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std::vector<Edge> edges_;
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std::vector<Edge> next_edge_; // for implementing removal
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std::vector<uint32_t> first_edge_; // the first edge for this vertex
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std::vector<uint8_t> vertex_degree_; // number of edges for this vertex
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};
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} // namespace cxxmph
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#endif // __CXXMPH_TRIGRAPH_H__
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