Programming

/* remove the first node it finds with value 'val' in L list */
edge *removeEdge (edge *L, int val)
{
      if( !L ) return NULL;

      if( L->key == val )
      {
          edge *temp = L->next;
          free (L);
          return temp;
      }

      L->next = removeEdge (L->next, val);

      return L;
}

/* deletes node with key u from G */
int g_deleteNode (graph *G, int u)
{
    int i;     
    
    if( G != NULL && (u >= 0 && u < G->nv) )
    {   
        for( i = 0; i < G->nv; i++ )
             /* because removeEdge is a list node removing function */
             G->adj[i]->next = removeEdge (G->adj[i]->next, u);
        
        for( i = u; i < G->nv; i++ )
             if( i + 1 < G->nv ) G->adj[i] = G->adj[i+1];
        
        free(G->adj[i]);
        
        G->nv--;
               
        return 1;
    }
    
    else
    {
        if( !G ) printf("Error: null graph.\n");
        else printf("Error: edge does not belong to graph.\n");        
        return 0;
    }
}

/* edge */
typedef struct edge
{
        int key,            /* node v of edge uv */
        struct edge *next;  
} edge;

/* graph */
typedef struct graph
{
        int nv;      /* number of nodes */
        edge **adj;  /* array of adjacency lists */
} graph;

 
for( i = u; i < G->nv; i++ )
    if( i + 1 < G->nv ) G->adj[i] = G->adj[i+1];
free(G->adj[i]);