21-easy-Merge_Two_Sorted_Lists.js

/**
21. Merge Two Sorted Lists

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

/**
 * Definition for singly-linked list.
 * function ListNode(val) {
 *     this.val = val;
 *     this.next = null;
 * }
 */
/**
 * @param {ListNode} l1
 * @param {ListNode} l2
 * @return {ListNode}
 */
var mergeTwoLists = function (l1, l2) {
  var result = new ListNode(0);
  var cur = result;

  while(l1 !== null && l2 !== null) {
    if (l1.val > l2.val) {
      cur.next = l2;
      l2 = l2.next;
    } else {
      cur.next = l1;
      l1 = l1.next;
    }
    cur = cur.next;
  }

  if (l1 !== null) {
    cur.next = l1;
  } else {
    cur.next = l2;
  }

  console.log(result);
  return result.next;
};