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 Insert a Node at the Tail of a Linked List



This challenge is part of a tutorial track by MyCodeSchool and is accompanied by a video lesson.

You are given the pointer to the head node of a linked list and an integer to add to the list. Create a new node with the given integer. Insert this node at the tail of the linked list and return the head node of the linked list formed after inserting this new node. The given head pointer may be null, meaning that the initial list is empty.


Link:

https://www.hackerrank.com/challenges/insert-a-node-at-the-tail-of-a-linked-list/problem


soultion:

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#include <bits/stdc++.h>

using namespace std;

class SinglyLinkedListNode {
    public:
        int data;
        SinglyLinkedListNode *next;

        SinglyLinkedListNode(int node_data) {
            this->data = node_data;
            this->next = nullptr;
        }
};

class SinglyLinkedList {
    public:
        SinglyLinkedListNode *head;

        SinglyLinkedList() {
            this->head = nullptr;
        }

};

void print_singly_linked_list(SinglyLinkedListNode* node, string sep, ofstream& fout) {
    while (node) {
        fout << node->data;

        node = node->next;

        if (node) {
            fout << sep;
        }
    }
}

void free_singly_linked_list(SinglyLinkedListNode* node) {
    while (node) {
        SinglyLinkedListNode* temp = node;
        node = node->next;

        free(temp);
    }
}

// Complete the insertNodeAtTail function below.

/*
 * For your reference:
 *
 * SinglyLinkedListNode {
 *     int data;
 *     SinglyLinkedListNode* next;
 * };
 *
 */
SinglyLinkedListNode* insertNodeAtTail(SinglyLinkedListNode* head, int data) {

    SinglyLinkedListNode* temp=new SinglyLinkedListNode(data);
    if(head==nullptr)
    {
        head=temp;
        return temp;
    }else {
        SinglyLinkedListNode* n=head;
        while(head->next!=nullptr){
             head=head->next;
         } 
         head->next=temp;
         return n;
    }

}

int main()
{
    ofstream fout(getenv("OUTPUT_PATH"));

    SinglyLinkedList* llist = new SinglyLinkedList();

    int llist_count;
    cin >> llist_count;
    cin.ignore(numeric_limits<streamsize>::max(), '\n');

  
    for (int i = 0; i < llist_count; i++) {
        int llist_item;
        cin >> llist_item;
        cin.ignore(numeric_limits<streamsize>::max(), '\n');

        SinglyLinkedListNode* llist_head = insertNodeAtTail(llist->head, llist_item);
        llist->head = llist_head;
    }


    print_singly_linked_list(llist->head, "\n", fout);
    fout << "\n";

    free_singly_linked_list(llist->head);

    fout.close();

    return 0;
}



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