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2026-09-07 18:48:16 +08:00
#ifndef INCLUDED_C_DIRECTEDCYCLE_H
#define INCLUDED_C_DIRECTEDCYCLE_H
#ifndef INCLUDED_C_DIGRAPH_H
#include <c_Digraph.h>
#endif /*INCLUDED_C_DIGRAPH_H*/
#ifndef INCLUDED_C_VERTEXIDLIST_H
#include <c_VertexIdList.h>
#endif /*INCLUDED_C_VERTEXIDLIST_H*/
/* ------------------------------------------------------------------------------------------------------------------ */
/* */
typedef struct {
c_bool_t* marked; /* Visited tracking array (size of graph->V) */
c_size_t* edge_to; /* edge_to[w] = last edge on path to w */
c_bool_t* on_stack; /* Keeps track of vertices currently on the recursive DFS stack */
c_VertexIdList_t cycle; /* Stores the cycle sequence if found */
c_Allocator_t allocator; /* Deep copy of the user-provided allocator */
} c_DirectedCycle_t;
/* ------------------------------------------------------------------------------------------------------------------ */
/* */
/**
* @brief Determines if the digraph has a directed cycle, and if so, finds one.
* @param allocator Explicit allocator context used to allocate internal routing arrays
*/
c_err_t c_DirectedCycle_Init(c_DirectedCycle_t* self, const c_Digraph_t* graph, c_Allocator_t* allocator);
/**
* @brief Releases internal tracking buffers
*/
void c_DirectedCycle_Destroy(c_DirectedCycle_t* self);
/**
* @brief Does the digraph have a directed cycle?
*/
C_STATIC_FORCE_INLINE c_bool_t c_DirectedCycle_HasCycle(c_DirectedCycle_t* self) {
if (!self) return C_FALSE;
return !c_VertexIdList_IsEmpty(&self->cycle);
}
/**
* @brief Gets the vertices on a directed cycle.
* @param out_cycle An initialized c_VertexIdList_t container to collect the sequence.
*/
c_err_t c_DirectedCycle_GetCycle(c_DirectedCycle_t* self, c_VertexIdList_t* out_cycle);
#endif /*INCLUDED_C_DIRECTEDCYCLE_H*/