beladiyahardik7 Hey guys is there is any problem in test case. I think there is problem in the 2 4 because for that atleast we require 3 node . and if i am correct then please correct the input as soon as possible
hejohnny Solution below in Java. The author probably wanted position paramaters exceeding the List size to be added to the end of the List.
Node InsertNth(Node head, int data, int position) { //Will Need to Return Head Node Node trackedHeadNode = head; Node nodeToInsert = new Node(); nodeToInsert.data = data; //Empty List - Returned newly created node or null if (head==null){return nodeToInsert;} //Inserting a Node ahead of the List if (position == 0){nodeToInsert.next = head; return nodeToInsert;} //Traverse the Singly Linked List to 1 Position Prior //Stop traversing if you reached the end of the List int currPosition = 0; while (currPosition < position -1 && head.next != null){ head = head.next; currPosition++; } //Inserting a Node in-between a List or at the end of of a List Node nodeAtPosition = head.next; head.next = nodeToInsert; head = head.next; head.next = nodeAtPosition; return trackedHeadNode; }
dev_shasif Well I think in custom input author does not want this
yashpalsinghdeo1 here is problem solution in python java c++ and c programming. https://solution.programmingoneonone.com/2020/07/hackerrank-insert-a-node-at-a-specific-position.html
dev_shasif Wasted a lot of my time
DarshakMehta Same here...
17331A0451 haaa
etayluz C solution:
Node* InsertNth(Node *head, int data, int position) { Node *newNode = (Node*)malloc(sizeof(Node)); newNode->data = data; if (head == NULL) { return newNode; } if (position == 0) { newNode->next = head; return newNode; } Node *currentNode = head; while (position - 1 > 0) { currentNode = currentNode->next; position--; } newNode->next = currentNode->next; currentNode->next = newNode; return head; }
srinivaschkdhi [deleted]kau5hik1 when head is NULL you need to make newNode->next = NULL, else the linked list wouldn't end with a NULL.
if (head == NULL) { newNode->next = NULL; return newNode; }
pranjal__g this solution will fail for 1st position.
ashokdey Here is my code in C++ that passed all the tests !
Node* InsertNth(Node *head, int data, int position) { Node *temp = head; if (head == nullptr) { // create a new node Node *mynode = new Node; mynode->data = data; mynode->next = nullptr; head = mynode; return head; } else { //count the number of nodes int count = 0; while (temp != nullptr) { ++count; temp = temp->next; } if (position == 0) { Node *mynode = new Node; mynode->data = data; mynode->next = head; head = mynode; return head; } else if (position >= count ) { // got to the last node temp = head; while (temp->next != nullptr) { temp = temp->next; } Node *mynode = new Node; mynode->data = data; mynode->next = nullptr; temp->next = mynode; return head; } else { temp = head; int pos = 0; while (temp->next != nullptr && pos < position-1) { ++pos; temp = temp->next; } Node *mynode = new Node; mynode->data = data; mynode->next = temp->next; temp->next = mynode; return head; } } }
saeven Much too long, you can simplify this by not iterating when you don't need to.
Node newNode = new Node(); newNode.data = data; Node current = head; if( position == 0 ){ newNode.next = head; return newNode; } int counter = 0; while( ++counter < position ){ current = current.next; } newNode.next = current.next; current.next = newNode; return head;
sveolon Why so long?
Node** p = &head; for(int i = 0; i < position; ++i) p = &(*p)->next; *p = new Node {data, *p}; return head;
milad Agreed in fact something like what you are sayign is the most elegant solution, I thought mine was :/
Node n = new Node(); n.data = data; Node cur = head; Node prev = null; int i = 0; while (i < position) { prev = cur; cur = cur.next; i++; // will crash if input head = null and pos > 0 // we assume no such inputs } n.next = cur; if (prev != null) { prev.next = n; return head; } return n;
ritulgoti i don't understand
marshal4world [deleted]marshal4world [deleted]marshal4world [deleted]
varunrisbud This is NOT a properly designed test case. Output is getting swapped when linked list starts with 2. Dont waste your time on this question.
pkssaini94 SAME PROBLEM
adelin_ghanayem I've already wasted like 2 hours !!!! by trying to solve it myself !!!
karid55 I thought i was the only one having issues until i read this i think the assignment instructions were poorly written
Hunter_ Either the test case that the author has included is broken or they have incorrectly described the test data and how the function should work. I was only able to pass it by including some special case code to get rid of a head node with data=2 and insert a tail node with a data=2. This challenge should be deleted until the author can fix the issues.
rafael_carrasco1 there is something wrong with the test case. What did you do to pass the test ?
Hunter_ I just hacked in a check at the beginning:
if (head->data == 2) { delete head; head = nullptr; }
And then another special case hack to insert a node containing 2 after the 4.
drover_ There is nothing wrong with the test case. Hunter_ likely had an off by one error.
Edit: Just FYI, the "hack" he used wouldn't work against virtually any other test case. Check the section of code where you iterate. There is likely an off by one error there if your output is incorrectly ordered.
aprobst1 I have this same issue, the head is 2 right from the beggining even though there is no 2 passed as input yet.
atique There is a flaw in the design of the problem's INPUT/OUTPUT.
- It should give head as NULL which it does not.
- There is an extra number expected at the end of the linked list
This is accepted code,
Node* InsertNth(Node *head, int data, int position) { if (position == 0) return head = new Node({data, new Node({2, NULL})}); Node* root = head; while (root->next && --position) root = root->next; root->next = new Node({data, root->next}); return head; }And, this is what accepted code should look like,
Node* InsertNth(Node *head, int data, int position) { if (head == NULL) return head = new Node({data, NULL}); if (position == 0) return head = new Node({data, head->next}); // strict checking as my habit if (position < 0) return NULL; Node* root = head; while (root->next && --position) root = root->next; root->next = new Node({data, root->next}); return head; }thiago_hirai I'm fairly certain that the test runner for C++ is broken. I wrote a nearly identical solution in Java and it passed, no problem.
shiva1996_sc your code is wrong
atique your comment is useless without some details
lauryndbrown This problem statement is pretty horrible. What exactly is the input format?
rubenavazquez It looks like from the Input box, 5 is the number of inputs and you have the position on the right side and the value to add on the left.
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