#ifndef INCLUDED_C_DIRECTEDDFS_H
#define INCLUDED_C_DIRECTEDDFS_H

#ifndef INCLUDED_C_DIGRAPH_H
#include <c_Digraph.h>
#endif /*INCLUDED_C_DIGRAPH_H*/

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

typedef struct {
    c_bool_t*      marked;      /* Visited tracking array (size of graph->V) */
    c_size_t       count;       /* Total number of vertices reachable from source(s) */
    c_Allocator_t  allocator;
}c_DirectedDFS_t;

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

/**
 * @brief Computes vertices reachable from a single source vertex 's'
 */
c_err_t c_DirectedDFS_Init(c_DirectedDFS_t* self, const c_Digraph_t* graph, c_size_t s, c_Allocator_t* allocator);

/**
 * @brief Computes vertices reachable from a list of multiple source vertices
 */
c_err_t c_DirectedDFS_InitMulti(c_DirectedDFS_t* self, const c_Digraph_t* graph, const c_size_t* sources, c_size_t source_count, c_Allocator_t* allocator);

/**
 * @brief Releases internal tracking buffers
 */
void c_DirectedDFS_Destroy(c_DirectedDFS_t* self);

/* ================================================================================================================== */
/* Inline Query Interfaces */

/**
 * @brief Is there a directed path from the source(s) to vertex 'v'?
 */
C_STATIC_FORCE_INLINE
c_bool_t c_DirectedDFS_HasPathTo(const c_DirectedDFS_t* self, c_size_t v, c_size_t total_V) {
    if (!self || !self->marked || v >= total_V) return C_FALSE;
    return self->marked[v];
}

/**
 * @brief Returns the total count of reachable vertices
 */
C_STATIC_FORCE_INLINE
c_size_t c_DirectedDFS_GetCount(const c_DirectedDFS_t* self) {
    return self ? self->count : 0;
}

#endif /*INCLUDED_C_DIRECTEDDFS_H*/