Study Plan For Algorithms - Part18
1. 反转链表
定义一个函数，输入一个链表的头节点，反转该链表并输出反转后链表的头节点。
方法一：
def reverseList(head):prev = Nonecur = headwhile cur:next = cur.nextcur.next = prevprev = curcur = nextreturn prev
方法二：
def reverseList(head):lst = []cur = headwhile cur:lst.append(cur.val)cur = cur.nextlst.reverse()new_head = Nonefor val in lst:new_node = ListNode(val)new_node.next = new_headnew_head = new_nodereturn new_head