#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>

#define MAX_NBRS    5
#define NAME_SIZE   32

typedef struct node_{

    char node_name[NAME_SIZE];
    struct node_ *nbrs[MAX_NBRS];
} node_t ;

void
add_nbr(node_t *node1, node_t *node2){

    int i = 0;
    for(; i < MAX_NBRS; i++){
        if(node1->nbrs[i]) continue;
        node1->nbrs[i] = node2;
        return;
    }
    /*Do not try to add more than MAX_NBRS*/
    assert(0);
} 

node_t *
create_new_node(char *name){

    node_t *node = calloc(1, sizeof(node_t));
    strncpy(node->node_name, name, NAME_SIZE);
    node->node_name[NAME_SIZE] = '\0';
    /*rest of the members is already NULL as 
     * we have used calloc*/
    return node;
}

#define ITERATE_NBRS_BEGIN(node, nbrnode)   \
{                                           \
    for( unsigned int i = 0 ; i < 5 && node->nbrs[i] != NULL ; i++ ){ \
        nbrnode = node->nbrs[i];
 /*<provide your implementation here>*/

#define ITERATE_NBRS_END }}
 /*<provide your implementation here>*/

#define ITERATE_ONE_HOP_NBRS_BEGIN(node, nbrnode)  \
{                                                  \
    for( unsigned int j = 0 ; j < 5 && node->nbrs[j] != NULL ; j++ ){ \
        for( unsigned int i = 0 ; i < 5 && node->nbrs[j]->nbrs[i] != NULL ; i++ ){ \
            if( node->nbrs[j]->nbrs[i] == node ) continue; \
            nbrnode = node->nbrs[j]->nbrs[i];

 /*<provide your implementation here>*/

#define ITERATE_ONE_HOP_NBRS_END  }}}  
 /*<provide your implementation here>*/
    
int
main(int argc, char **argv){

/*Problem 2  : In thie Question, I have created a graph as shown in the diagram below.*/

/*Let us create the following graph now*/
/*
         A-------------B------------C---------H
         |             |            |
         |             |            |
         |             |            |
         |             |            |
         |             |            |
         E-------------D------------F---------G
*/

    /*First I have created the nodes of the graph*/    
    node_t *A = create_new_node("A");
    node_t *B = create_new_node("B");
    node_t *C = create_new_node("C");
    node_t *D = create_new_node("D");
    node_t *E = create_new_node("E");
    node_t *F = create_new_node("F");
    node_t *G = create_new_node("G");
    node_t *H = create_new_node("H");


    /*Now i am setting up the edges connecting two nodes of the graph using function add_nbr().
     * Result is - Graph will be created exactly same as drawn above*/
    add_nbr(A,B);
    add_nbr(A,E);

    add_nbr(B,A);
    add_nbr(B,D);
    add_nbr(B,C);

    add_nbr(C,B);
    add_nbr(C,F);
    add_nbr(C,H);
    
    add_nbr(D,B);
    add_nbr(D,E);
    add_nbr(D,F);
    
    add_nbr(E,A);
    add_nbr(E,D);

    add_nbr(F,C);
    add_nbr(F,D);
    add_nbr(F,G);

    add_nbr(G,F);

    add_nbr(H,C);
    
    node_t *nbr = NULL;
    printf("Nbrs of A : \n");
    ITERATE_NBRS_BEGIN(A, nbr){
        
        printf("Nbr name = %s\n", nbr->node_name);
    } ITERATE_NBRS_END;
    
    printf("Nbrs of H : \n");
    ITERATE_NBRS_BEGIN(H, nbr){
        
        printf("Nbr name = %s\n", nbr->node_name);
    } ITERATE_NBRS_END;

    printf("Nbrs of D : \n");
    ITERATE_NBRS_BEGIN(D, nbr){
        
        printf("Nbr name = %s\n", nbr->node_name);
    } ITERATE_NBRS_END;

    printf("One hop Nbrs of A : \n");
    ITERATE_ONE_HOP_NBRS_BEGIN(A, nbr){

        printf("Nbr name = %s\n", nbr->node_name);
    } ITERATE_ONE_HOP_NBRS_END;

    return 0;
}