74 lines
2.9 KiB
C
74 lines
2.9 KiB
C
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#ifndef INCLUDED_C_FLOYDWARSHALL_H
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#define INCLUDED_C_FLOYDWARSHALL_H
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#ifndef INCLUDED_C_EDGEWEIGHTEDDIGRAPH_H
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#include <c_EdgeWeightedDigraph.h>
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#endif /*INCLUDED_C_EDGEWEIGHTEDDIGRAPH_H*/
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#ifndef INCLUDED_C_EDGEIDLIST_H
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#include <c_EdgeIdList.h>
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#endif /*INCLUDED_C_EDGEIDLIST_H*/
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/* ------------------------------------------------------------------------------------------------------------------ */
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/* */
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typedef struct {
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double** dist_to; /* dist_to[u][v] = distance of shortest path from u to v */
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c_size_t** next_vertex; /* next_vertex[u][v] = immediate next vertex on path from u to v */
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c_size_t** edge_to; /* edge_to[u][v] = global directed edge_id for choice transition u -> next */
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c_size_t V; /* Total number of vertices in the digraph */
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c_bool_t has_neg_cycle; /* Flag indicating if a negative cycle was intercepted */
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c_Allocator_t allocator; /* Deep copy of the user-provided allocator */
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} c_FloydWarshall_t;
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/* ------------------------------------------------------------------------------------------------------------------ */
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/* */
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/**
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* @brief Computes all-pairs shortest paths in a general edge-weighted digraph.
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* @param allocator Explicit allocator context used to configure internal tracking state memory
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*/
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c_err_t c_FloydWarshall_Init(c_FloydWarshall_t* self, c_EdgeWeightedDigraph_t* graph, c_Allocator_t* allocator);
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/**
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* @brief Releases internal tracking buffers safely.
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*/
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void c_FloydWarshall_Destroy(c_FloydWarshall_t* self);
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/**
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* @brief Is there a directed path from vertex 'u' to vertex 'v'?
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*/
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C_STATIC_FORCE_INLINE c_bool_t c_FloydWarshall_HasPath(c_FloydWarshall_t* self, c_size_t u, c_size_t v) {
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if (!self || self->has_neg_cycle || u >= self->V || v >= self->V || !self->dist_to) return C_FALSE;
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return self->dist_to[u][v] < DBL_MAX;
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}
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/**
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* @brief Returns the distance of the shortest path from vertex 'u' to vertex 'v'.
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* @return Distance value, or DBL_MAX if unreachable / parameter error
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*/
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C_STATIC_FORCE_INLINE double c_FloydWarshall_Dist(c_FloydWarshall_t* self, c_size_t u, c_size_t v) {
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if (!self || u >= self->V || v >= self->V || !self->dist_to) return DBL_MAX;
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if (self->has_neg_cycle) return -DBL_MAX;
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return self->dist_to[u][v];
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}
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/**
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* @brief Does the edge-weighted digraph contain any negative cycles?
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*/
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C_STATIC_FORCE_INLINE
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c_bool_t c_FloydWarshall_HasNegativeCycle(c_FloydWarshall_t* self) {
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return self ? self->has_neg_cycle : C_FALSE;
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}
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/**
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* @brief Reconstructs the exact shortest path from vertex 'u' to vertex 'v' and appends it to out_path.
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* @param out_path An initialized c_EdgeIdList_t container to collect the sequence of global directed edge_ids.
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*/
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c_err_t c_FloydWarshall_Path(c_FloydWarshall_t* self, c_size_t u, c_size_t v, c_EdgeIdList_t* out_path);
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#endif /*INCLUDED_C_FLOYDWARSHALL_H*/
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