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javascriptarraysnodelist

is it possible to convert an Array to a NodeList in javascript? leetcode problem --Linked lists--

I am trying to solve a leetcode problem and I think I have figured it out, the problem is that my function returns an Array with the correct Answer and the problem specifies that I must return a NodeList,

I can't figure out how to create a NodeList without reaching to the DOM, or to transform my Array to NodeList.

The problem is:

Merge two sorted linked lists and return it as a new sorted list. The new list should be made by splicing together the nodes of the first two lists.

Example:

Input: 1->2->4, 1->3->4 Output: 1->1->2->3->4->4

my code is :

const listOne = [1, 2, 4];
const listTwo = [1, 3, 4];

function myFunction(l1, l2) {
  let lslength;
  let newList = [];
  if (l1.length >= l2.length) {
    lslength = l1.length;
  } else {
    lslength = l2.length;
  }
  for (let i = 0; i < lslength; i++) {
    if (l1[i] === l2[i]) {
      newList.push(l1[i]);
      newList.push(l2[i]);
    } else if (l1[i] < l2[i]) {
      newList.push(l1[i]);
      newList.push(l2[i]);
    } else if (l1[i] > l2[i]) {
      newList.push(l2[i]);
      newList.push(l1[i]);
    } else if (l1[i]) {
      newList.push(l1[i]);
    } else {
      newList.push(l2[i]);
    }
  }
  return newList;
}

myFunction(listOne, listTwo);

--------EDIT--------- ok so I really didnt understand the problem because its about Linked Lists, now I know, thank you

Solution

  • You don't need to do that.

    The test cases are represented like arrays for user simplicity I guess. Though, LinkedList and array are two different data types. Your function is returning an array, which is not a desired output here. The desired output is simply a merged linked list, not a merged array.

    Here we'd use a sentinel node to merge two linked lists. This'll get accepted:

    /**
 * Definition for singly-linked list.
 * function ListNode(val, next) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.next = (next===undefined ? null : next)
 * }
 */
/**
 * @param {ListNode} l1
 * @param {ListNode} l2
 * @return {ListNode}
 */
var mergeTwoLists = function(l1, l2) {
    var sentinel = {
        val: -1,
        next: null
    };

    var curr = sentinel;
    while (l1 && l2) {
        if (l1.val > l2.val) {
            curr.next = l2;
            l2 = l2.next;
        } else {
            curr.next = l1;
            l1 = l1.next;
        }
        curr = curr.next;
    }

    curr.next = l1 || l2;

    return sentinel.next;
};

    References