64 lines
2.4 KiB
C
64 lines
2.4 KiB
C
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#ifndef INCLUDED_C_BREADTHFIRSTDIRECTEDPATHS_H
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#define INCLUDED_C_BREADTHFIRSTDIRECTEDPATHS_H
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#ifndef INCLUDED_C_DIGRAPH_H
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#include <c_Digraph.h>
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#endif /*INCLUDED_C_DIGRAPH_H*/
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#ifndef INCLUDED_C_VERTEXIDLIST_H
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#include <c_VertexIdList.h>
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#endif /*INCLUDED_C_VERTEXIDLIST_H*/
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/* ------------------------------------------------------------------------------------------------------------------ */
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/* */
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typedef struct {
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c_bool_t* marked; /* Visited tracking array (size of graph->V) */
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c_size_t* edge_to; /* edge_to[w] = last edge on shortest path from s to w */
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c_size_t* dist_to; /* dist_to[w] = number of edges on shortest path from s to w */
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c_size_t s; /* Source vertex */
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c_Allocator_t allocator; /* Deep copy of the user-provided allocator */
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} c_BreadthFirstDirectedPaths_t;
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/* ------------------------------------------------------------------------------------------------------------------ */
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/* */
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/**
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* @brief Computes shortest directed paths from a single source vertex 's' using BFS
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* @param allocator Explicit allocator context used to allocate internal routing arrays
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*/
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c_err_t c_BreadthFirstDirectedPaths_Init(c_BreadthFirstDirectedPaths_t* self, const c_Digraph_t* graph, c_size_t s, c_Allocator_t* allocator);
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/**
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* @brief Releases internal tracking buffers
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*/
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void c_BreadthFirstDirectedPaths_Destroy(c_BreadthFirstDirectedPaths_t* self);
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/**
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* @brief Is there a directed path from the source 's' to vertex 'v'?
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*/
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C_STATIC_FORCE_INLINE
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c_bool_t c_BreadthFirstDirectedPaths_HasPathTo(c_BreadthFirstDirectedPaths_t* self, c_size_t v, c_size_t total_V) {
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if (!self || !self->marked || v >= total_V) return C_FALSE;
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return self->marked[v];
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}
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/**
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* @brief Returns the number of edges in a shortest path from the source 's' to vertex 'v'
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* @return Distance value, or C_SIZE_MAX if unreachable / parameter error
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*/
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C_STATIC_FORCE_INLINE
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c_size_t c_BreadthFirstDirectedPaths_DistTo(c_BreadthFirstDirectedPaths_t* self, c_size_t v, c_size_t total_V) {
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if (!self || v >= total_V || !self->marked[v]) return C_SIZE_MAX;
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return self->dist_to[v];
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}
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/**
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* @brief Reconstructs the exact shortest path from source 's' to vertex 'v' and appends it to out_path
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*/
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c_err_t c_BreadthFirstDirectedPaths_PathTo(c_BreadthFirstDirectedPaths_t* self, c_size_t v, c_size_t total_V, c_VertexIdList_t* out_path);
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#endif /*INCLUDED_C_BREADTHFIRSTDIRECTEDPATHS_H*/
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