题解 | #反转链表#

反转链表：用一个栈

stack<int> s;
ListNode * p = pHead;
while(p != nullptr)
{
s.push(p->val);
p = p->next;
}
ListNode * q = pHead;
while(q != nullptr)
{
q->val = s.top();
s.pop();
q = q->next;
}
return pHead;
}
```</int>