数据结构 python 版本

 1 class Node(object):
 2     def __init__(self,element=None):
 3         self.element = element
 4         self.next = None
 5 
 6 # 这种创建链表的方法是非常野鸡的，这里主要是为了演示
 7 head = Node()
 8 n1 = Node(111)
 9 n2 = Node(222)
10 n3 = Node(333)
11 head.next = n1
12 n1.next = n2
13 n2.next = n3
14 
15 def log_link_list(head):
16     """
17     打印链表中所有的元素
18     """
19     n = head.next
20     while n.next is not None:
21         print(n.element)
22         n = n.next
23     print(n.element)
24     
25     
26 def append(head,element):
27     """
28     在链表的末尾添加元素
29     """
30     n = head
31     while n.next is not None:
32         n = n.next
33     node = Node()
34     n.next = node
35     node.element = element
36     
37     
38 def preappend(head,element):
39     """
40     链表的头插法
41     """
42     node = Node(element)
43     node.next = head.next
44     head.next = node
45     
46     
47 def pop(head):
48     tail = head
49     while tail.next is not None:
50         tail = tail.next
51     # 拿到最后一个元素的 pointer 了
52     n = head
53     while n.next is not tail:
54         n = n.next
55     n.next = None
56     return tail.element
57     
58 preappend(head,999)   
59 append(head,666)
60 log_link_list(head)
61 
62 pop(head)
63 log_link_list(head)

class Tree(object):
    def __init__(self,element=None):
        self.element = element
        self.left = None
        self.right = None
        
    def traversal(self):
        """
        二叉树的前序,中序，后续遍历
        改变 print 的位置就可以
        """
       
        if self.left is not None:
            self.left.traversal()
        if self.right is not None:
            self.right.traversal()
        print(self.element)
            
    def reverse(self):
        """
        交换左右子树
        """
        self.left, self.right = self.right, self.left
        if self.left is not None:
            self.left.reverse()
        if self.right is not None:
            self.right.reverse()

def test():
    # 手动构建二叉树，这种方法非常野鸡。就只有在学习的时候用
    # 在实际的应用中，一般都是自动生成的
    
    t = Tree(0)
    left = Tree(1)
    right = Tree(2)
    t.left = left
    t.right = right
    
    t.traversal()
    
if __name__ == ‘__main__‘:
    test()