单链表反转

class Node(object):

    def __init__(self, data, next):
        self.data = data
        self.next = next


def reverse(head):
    if head is None or head.next is None:
        return head

    pre = None
    current = head
    while current:
        tmp = current
        current = current.next
        tmp.next = pre
        pre = tmp
        print_node(pre)

    return pre


def print_node(head):
    result = ""
    while head:
        result += str(head.data)+"->"
        head = head.next
    print result


if __name__ == "__main__":
    h = Node(1, Node(2, Node(3, Node(4, Node(5, None)))))
    h1 = reverse(h)