dfs.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
typedef struct node node;
struct node
{
    int id;
    node* next;
};

void dfs_visit(int i , node list[] , int array[] ,int* position , bool is_visited[])
{
    if(is_visited[i] == true)
    return;
    is_visited[i] = true;
    array[*position] = i;
    (*position) += 1;

    while(list[i].next!= NULL)
    {
        list[i] = *(list[i].next);
        int a = list[i].id;
        dfs_visit(list[i].id , list , array , position , is_visited);
    }
}
int main()
{
    int n , e; // e is the number of edges that will be inputted
    scanf("%d %d",&n , &e);

    int array[n]; // will store the dfs traversal of the graph
    int posn=0;// (optional)tells where we have to add element in array[]

    bool is_visited[n+1];
    for(int i=1;i<=n;i++)
    is_visited[i] = false;

    node* list;
    list = (node*)malloc((n+1)*sizeof(node));
    for(int i=1;i<=n;i++)
    list[i].next = NULL;

    for(int i=0;i<e;i++)
    {
        int start , end;
        scanf("%d %d",&start ,&end);
        node *temp;
        temp = (node*)malloc(sizeof(node));
        temp->id = end;
        temp->next = list[start].next;
        list[start].next = temp;
    }

    dfs_visit(1 , list , array , &posn ,is_visited);

    for(int i=0;i<n;i++)
    printf("%d ", array[i]);

    printf("\n%d\n", posn);
}