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

typedef struct AdjListNode
{
    int dest;
    struct AdjListNode* next;
}Node_T;

typedef struct AdjList
{
    Node_T *head;
}List_T;

typedef struct Graph
{
    int V;
    List_T* array;
}Graph_T;

Node_T* newAdjListNode(int dest)
{
    Node_T* newNode = (Node_T*) malloc(sizeof(Node_T));
    newNode->dest = dest;
    newNode->next = NULL;
    return newNode;
}

Graph_T* createGraph(int V)
{
    Graph_T* graph = (Graph_T*) malloc(sizeof(Graph_T));
    graph->V = V;

    graph->array = (List_T*) malloc(V * sizeof(List_T));

    int i;
    for (i = 0; i < V; ++i)
        graph->array[i].head = NULL;
    return graph;
}

void addEdge(Graph_T* graph, int src, int dest)
{
    Node_T* newNode = newAdjListNode(dest);
    newNode->next = graph->array[src].head;
    graph->array[src].head = newNode;

    newNode = newAdjListNode(src);
    newNode->next = graph->array[dest].head;
    graph->array[dest].head = newNode;
}
void printGraph(Graph_T* graph)
{
    int v;
    for (v = 0; v < graph->V; ++v)
    {
        Node_T* pCrawl = graph->array[v].head;
        printf("\n Adjacency list of vertex %d\n head ", v);
        while (pCrawl)
        {
            printf("-> %d", pCrawl->dest);
            pCrawl = pCrawl->next;
        }
        printf("\n");
    }
}
int main()
{
    int V = 5;
    Graph_T* graph = createGraph(V);
    addEdge(graph, 0, 1);
    addEdge(graph, 0, 4);
    addEdge(graph, 1, 2);
    addEdge(graph, 1, 3);
    addEdge(graph, 1, 4);
    addEdge(graph, 2, 3);
    addEdge(graph, 3, 4);

    // print the adjacency list representation of the above graph
    printGraph(graph);

    return 0;
}