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  1. Prepare
  2. Data Structures
  3. Linked Lists
  4. Insert a node at a specific position in a linked list
  5. Discussions

Insert a node at a specific position in a linked list

  • hejohnny
     + 17 comments

    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;
}