#ifndef INCLUDED_C_BIPARTITE_H
#define INCLUDED_C_BIPARTITE_H

#ifndef INCLUDED_C_GRAPH_H
#include <c_Graph.h>
#endif /*INCLUDED_C_GRAPH_H*/


#ifndef INCLUDED_C_VERTEXIDLIST_H
#include <c_VertexIdList.h>
#endif /*INCLUDED_C_VERTEXIDLIST_H*/


/* ------------------------------------------------------------------------------------------------------------------ */
/*  */

typedef struct {
    c_bool_t*           marked;       // marked[v] = has vertex v been discovered?
    c_bool_t*           color;        // color[v]  = color assigned to vertex v (true/false)
    c_size_t*           edge_to;      // edge_to[v] = last vertex on DFS path to v
    c_VertexIdList_t    cycle;       // Stores an odd-length cycle if graph is not bipartite
    c_bool_t            is_bipartite; // Global bipartite validation status flag
    c_size_t            V;      // Cached local vertex bound tracker
    c_Allocator_t       allocator;    // Memory allocator reference instance copy
} c_Bipartite_t;

/* ------------------------------------------------------------------------------------------------------------------ */
/*  */

/**
 * @brief Determines whether an undirected graph is bipartite.
 * @param self Pointer to the uninitialized bipartite tracking structure.
 * @param G Pointer to the constant target graph object to verify.
 * @param allocator Memory allocator instance pointer to deploy.
 * @return C_SUCCESS on success, or an error status code on allocation failure.
 */
c_err_t  c_Bipartite_Init(c_Bipartite_t* self, const c_Graph_t* G, c_Allocator_t* allocator);

/**
 * @brief Drops all internal allocation states within the bipartite instance safely.
 */
void     c_Bipartite_Destroy(c_Bipartite_t* self);

/**
 * @brief Returns true if the graph is bipartite.
 */
c_bool_t c_Bipartite_IsBipartite(const c_Bipartite_t* self);

/**
 * @brief Returns the color assignment of vertex v.
 */
c_bool_t c_Bipartite_Color(const c_Bipartite_t* self, c_VertexId_t v);

/**
 * @brief Returns an odd-length cycle if the graph is not bipartite, or an empty list if it is.
 */
const c_VertexIdList_t* c_Bipartite_Cycle(const c_Bipartite_t* self);

#endif /*INCLUDED_C_BIPARTITE_H*/