python 递归和非递归实现 统计链表节点个数

 非递归版本：

class ListNode:
    def __init__(self, x,next=None):
        self.val = x
        self.next = next
def sortInList(head):
    cout=0
    while head:
        cout+=1
        head = head.next
    return cout
if __name__ == '__main__':
    root=ListNode(1,ListNode(2,ListNode(3,ListNode(4,ListNode(5,None)))))
    len=sortInList(root)
    print('The length of the linked list is ' + str(len))

递归版本：

class ListNode:
    def __init__(self, x,next=None):
        self.val = x
        self.next = next

def sortInList(head,cout):
    if head:
        cout+=1
        head=head.next
    else:
        return cout
    return sortInList(head,cout)
if __name__ == '__main__':
    root=ListNode(1,ListNode(2,ListNode(3,ListNode(4,ListNode(5,None)))))
    cout = 0
    len=sortInList(root,cout)# 输入头节点
    print('The length of the linked list is ' + str(len))