/function ListNode(x){ this.val = x; this.next = null; }/ function Merge(pHead1, pHead2) { // write code here if(!pHead1) { return pHead2 } if(!pHead2) { return pHead1 } let head if(pHead1.val < pHead2.val) { head = pHead1 head.next = Merge(pHead1.next,pHead2) } else { head = pHead2 head.next = Merge(pHead2.next,pHead1) } return head } module.exports = { Merge : Merge };