0021-merge-two-sorted-lists.js

/**
 * 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) {
  let listNode = new ListNode

  let cur = listNode
  while(l1 && l2) {
    if(l1.val > l2.val) {
      cur.next = l2
      l2 = l2.next
    } else {
      cur.next = l1
      l1 = l1.next
    }
    cur = cur.next
  }
  cur.next = l1 || l2
  return listNode.next
};

// 2022.02.11 done