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206. Reverse Linked List.py
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206. Reverse Linked List.py
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class ListNode:
def __init__(self,initdata):
self.val = initdata
self.next = None
def getData(self):
return self.val
def getNext(self):
return self.next
def setData(self,newdata):
self.val = newdata
def setNext(self,newnext):
self.next = newnext
def tolist(self):
p = self
re = []
while p!=None:
re.append(p.val)
p=p.next
return re
class OrderedList:
def __init__(self):
self.head = None
def search(self,item):
current = self.head
found = False
stop = False
while current != None and not found and not stop:
if current.getData() == item:
found = True
else:
if current.getData() > item:
stop = True
else:
current = current.getNext()
return found
def add(self,li):
if isinstance(li,int):
li = [li]
for item in li:
current = self.head
previous = None
stop = False
while current != None and not stop:
if current.getData() > item:
stop = True
else:
previous = current
current = current.getNext()
temp = ListNode(item)
if previous == None:
temp.setNext(self.head)
self.head = temp
else:
temp.setNext(current)
previous.setNext(temp)
def size(self):
current = self.head
count = 0
while current != None:
count = count + 1
current = current.getNext()
return count
def tolist(self):
p = self.head
re = []
while p!=None:
re.append(p.val)
p=p.next
return re
class Solution(object):
def reverseList(self, head):
"""
:type head: ListNode
:rtype: ListNode
"""
p = head
if not p or not p.next : return p
p1 = head.next
p.next = None
tmp = None
while p1:
tmp = p1.next or None
p1.next = p
p = p1
p1 = tmp
return p
l = OrderedList()
l.add([1,2,3,4,5])
h = l.head
p = Solution().reverseList(h)
print p.next.val