题解 | #反转链表#

利用栈，先把元素都压入栈中，再建立一个头结点HeadNode，放入第一个出栈元素，这个头结点保持不动，方便后续返回链表，新建一个工具指针cuur，用来将元素依次从栈中取出存入链表，用完之后他就没用了，用始终指向最前面的HeadNode来输出链表

    this.val = x;
    this.next = null;
}*/
function ReverseList(pHead) {
  // write code here
  if (pHead == null || pHead.next == null) return pHead;
  var stack = [];
  //压栈
  while (pHead != null) {
    stack.push(pHead);
    pHead = pHead.next;
  }
  var headNode = stack.pop();
  var curr = headNode;
  while (stack.length) {
    curr.next = stack.pop();
    curr = curr.next;
    curr.next = null;
  }
  return headNode;
}
module.exports = {
  ReverseList: ReverseList,
};