链表&&数组

1.链表转数组

function listToArray(list){
  const res = [];
  while(list !== null){
    res.push(list.val)
    list = list.next
  }
  return res;
}

2.数组转链表

function arrayToList(arr){
  if(!arr.length){
    return null
  }
  let head = {val:arr[0],next:null}
  let pnode = head
  let node = null;
  for(let i = 1; i < arr.length; i++){
    node = {val:arr[i],next:null}
    pnode.next = node;
    pnode = pnode.next
  }
  return head;
}