题解 | #4.合并两个排序的链表#

so esay

function Merge(pHead1, pHead2)
{
  let empty = {};
  let pre = empty;
  while(pHead1!=null && pHead2!=null){
    if(pHead1.val < pHead2.val){
      pre.next = pHead1;
      pHead1 = pHead1.next;
    }else{
      pre.next = pHead2;
      pHead2 = pHead2.next;
    }
    pre = pre.next;
  }
  pre.next = pHead1!=null ? pHead1 : pHead2;
  return empty.next
}