#include <iostream>
using namespace std;

struct Node{
    int data;
    struct Node *next;
};

int hash_(int key)
{
    return key%10;
}

void myinsert(struct Node **H,int ele){
    struct Node *p = *H;
    struct Node *t = new Node;
    t->data = ele;
    t->next = NULL;
    if(*H==NULL){               // Important to compare index address(*H) rather than p with NULL
        *H=t;
    }else{
        while(p->next!=NULL){
            p=p->next;
        }
        p->next = t;
    }
}

void insert(struct Node *HT[], int ele){
    int index=hash_(ele);
    myinsert(&HT[index],ele);
}


void print_at_index(struct Node *HT[],int index){
    struct Node *p= HT[index];
    if(p==NULL){
       cout << "No elements here!";
       return;
    }
    while(p!=NULL){
        cout << p->data << " ";
        p=p->next;
    }
    cout << endl;
}


void print_all(struct Node *HT[]){
    for(int i=0;i<10;i++){
        struct Node *p= HT[i];
        if(p==NULL){
            cout << i << " -> NULL" << endl;
        }else{
            cout << i << " -> ";
            while(p!=NULL){
                cout << p->data << " -> ";
                p=p->next;
            }
            cout << "NULL";
            cout << endl;
        }
    }
}

void del(struct Node * HT[],int key){
    int index = hash_(key);
    struct Node *p = HT[index], *q=NULL;
    if(p->next==NULL){                              // Only one node is present
        HT[index] = NULL;
        delete p;
    }else if(key == p->data && p->next!=NULL){      // If first node has the key
        HT[index] = p->next;
        delete p;
    }else{
        while(p->data != key){                      // Search for key, else return not found
            q=p;
            p=p->next;
            if(p==NULL and q->data!=key){
                cout << key << " not found!" << endl;
                return;
            }
        }
        q->next = p->next;
        delete p;
    }
}

int main(){
    struct Node *HT[10];

    for(int i=0;i<10;i++){
        HT[i]=NULL;
    }

    insert(HT,12);
    insert(HT,22);

    print_at_index(HT,2);           // To print all keys at a particular index
    cout << endl;
    //print_all(HT);                // To print all the indices in the form of a table

    del(HT,12);                     // Delete key-12

    print_all(HT);
}