Python實現反轉鍊錶

將鍊錶進行反轉

輸入: 1->2->3->4->5->null

輸出: 5->4->3->2->1->null

儲存上乙個節點的節點資訊

繼續處理後面的節點

class

listnode
:def
__init__
(self,val,
next
=none):
ifisinstance
(val,
int)
: self.val = val
self.
next
=next
elif
isinstance
(val,
list):
self.val = val[0]
self.
next
=none
head = self
for i in
range(1
,len
(val)):
node = listnode(val[i]
) head.
next
= node
head = head.
next
class
solution
:def
reverselist
(self, head: listnode)
-> listnode:
#用來記錄上乙個節點
prev =
none
#儲存當前的鍊錶
curr = head
while curr !=
none
:#記錄後乙個節點
nex = curr.
next
#改變節點的指向,反轉鍊錶
curr.
next
= prev
prev = curr
#繼續處理後面的鍊錶
curr = nex
return prev
l =[1,
2,3,
4,5]
list_node = listnode(l)
obj = solution(
)reve_list_node = obj.reverselist(list_node)
while reve_list_node:
print
(reve_list_node.val)
reve_list_node = reve_list_node.
next

class

solution
:def
reverselist
(self, head: listnode)
-> listnode:
if head ==
none
or head.
next
==none
:return head
#繼續遞迴後乙個節點
newhead = self.reverselist(head.
next
)#反轉節點
head.
next
.next
= head
head.
next
=none
return newhead

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