[ http://www.lintcode.com/en/problem/count-linked-list-nodes/ ]
# Python
"""
Definition of ListNode
class ListNode(object):
def __init__(self, val, next=None):
self.val = val
self.next = next
"""
class Solution:
"""
@param: head: the first node of linked list.
@return: An integer
"""
def countNodes(self, head):
# write your code here
p = head
count = 0
while p != None:
p = p.next
count += 1
return count
