GetNodeValue.cs

// This challenge is part of a tutorial track by MyCodeSchool

// You’re given the pointer to the head node of a linked list and a specific position. Counting backwards from the tail node of the linked list, get the value of the node at the given position. A position of 0 corresponds to the tail, 1 corresponds to the node before the tail and so on.

// Input Format

// You have to complete the int getNode(SinglyLinkedListNode* head, int positionFromTail) method which takes two arguments - the head of the linked list and the position of the node from the tail. positionFromTail will be at least 0 and less than the number of nodes in the list. You should NOT read any input from stdin/console.

// The first line will contain an integer , the number of test cases. 
// Each test case has the following format: 
// The first line contains an integer , the number of elements in the linked list. 
// The next  lines contains, an element each denoting the element of the linked list. 
// The last line contains an integer  denoting the position from the tail, whose value needs to be found out and returned.

// Constraints

// , where  is the  element of the linked list.
// Output Format

// Find the node at the given position counting backwards from the tail. Then return the data contained in this node. Do NOT print anything to stdout/console.

// The code in the editor handles output. 
// For each test case, print the value of the node, each in a new line.
    // Complete the getNode function below.

    /*
     * For your reference:
     *
     * SinglyLinkedListNode {
     *     int data;
     *     SinglyLinkedListNode next;
     * }
     *
     */
    static int getNode(SinglyLinkedListNode head, int positionFromTail) {
        int count = 0;  
        var current = head; 
        var data = 0;
        //count nodes
        while (current != null)
        {            
            count++;            
            current = current.next;        
        }
        //find position
        var position = count - positionFromTail;
        current = head;
        //loop to position and return data 
        for (var i=0; i<position; i++)
        {            
            if (i == position-1)
            {
                data = current.data; 
            }
            if (current.next != null)
            {
                current = current.next;
            }            
        }
        
        return data;   
    }