def reverseBetween(self, head, m, n):
"""
:param head: ListNode
:param m: int
:param n: int
:return: ListNode
"""
dummyhead = Node()
dummyhead.next = head
cur = head
index = 1
pre = dummyhead
while index <= n:
if index >= m:
"""todo"""
if index == m:
m_node = cur
m_pre = pre
if index == n:
n_node = cur
n_next = cur.next
next = cur.next
cur.next = pre
pre = cur
cur = next
index += 1
else:
pre = cur
cur = cur.next
index += 1
m_pre.next = n_node
m_node.next = n_next
return dummyhead
def reverseList(self, head):
"""
:param head: ListNode
:return: ListNode
"""
dummyhead = Node()
dummyhead.next = head
cur = dummyhead.next
pre = None
while cur != None:
next = cur.next
cur.next = pre
pre = cur
cur = next
dummyhead.next = pre
return dummyhead