leetcode之Intersection of Two Linked Lists

# Definition for singly-linked list.
# class ListNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution(object):
def getIntersectionNode(self, headA, headB):
"""
:type head1, head1: ListNode
:rtype: ListNode
"""
if not headA:
return None
if not headB:
return None
lenofheadA = 0
lenofheadB = 0
headB1 = headB
headA1 = headA
while headB1:
lenofheadB += 1
headB1 = headB1.next
while headA1:
lenofheadA += 1
headA1 = headA1.next
deviation = abs(lenofheadA - lenofheadB)
if lenofheadA >= lenofheadB:
for i in range(deviation):
headA = headA.next
NumofStep = 0
while NumofStep < lenofheadB:
if headA == headB:
return headB
else:
headB = headB.next
headA = headA.next
NumofStep += 1
else:
return None
else:
for i in range(deviation):
headB = headB.next
NumofStep = 0
while True:
if headA == headB:
return headB
else:
headB = headB.next
headA = headA.next
NumofStep += 1
else:
return None