Python数据结构之二叉树
本来打算一个学期分别用C++、Python、Java实现数据结构，看来要提前了
这个是Python版本，我写的数据结构尽量保持灵活性，本文bt1是一般的插入法建立二叉树结构，bt2就是可以任意输入，至于树的高度的递归和非递归实现等等，在C++里实现过就不再重复。
#Date : 2013-9-12
#Author : DVD0423
#Function : 二叉树
class Node:
def __init__(self, value = None, left = None, right = None):
self.value = value
self.left = left
self.right = right
def visit(self):
print(self.value)
class BTree:
def __init__(self, root = Node()):
self.root = root
def CreateBTree(self, _list = []):
#层序遍历，产生二叉树结构
length = len(_list)
node = []
for i in range(length):
node.append(Node())
node[i].value = _list[i]
front = 0
rear = 0
while(rear != length):
rear = rear + 1
if rear >= length:
break
node[front].left = node[rear]
rear = rear + 1
if rear >= length:
break
node[front].right = node[rear]
front = front + 1
#下面这句没有必要，因为初始化就是None,但是逻辑上要有
while(front != length):
node[front].left = None
node[front].right = None
front = front + 1
self.root = node[0]
def Traverse(self, method):
def PostOrder(node):
if node:
PostOrder(node.left)
PostOrder(node.right)
node.visit()
def InOrder(node):
if node:
InOrder(node.left)
node.visit()
InOrder(node.right)
def PreOrder(node):
if node:
node.visit()
PreOrder(node.left)
PreOrder(node.right)
def NoRecTraverse(node):
ls = []
while True:
if node:
ls.append(node)
node.visit()
node = node.left
else:
if len(ls) != 0:
node = ls.pop()
node = node.right
if len(ls) == 0 and node == None:
break
if method is 1:
print("后序遍历")
PostOrder(self.root)
elif method is 2:
print("中序遍历")
InOrder(self.root)
elif method is 3:
print("前序遍历")
PreOrder(self.root)
else:
print("非递归先序遍历")
NoRecTraverse(self.root)
def InputInt():
seq = []
while True:
ch = input()
if ch is 'e':
break
seq.append(int(ch))
return seq
if __name__ == '__main__':
#两种方式建立二叉树
print("二叉树1：")
node3 = Node(3)
node2 = Node(2)
node1 = Node(1, node2, node3)
bt1 = BTree(node1)
bt1.Traverse(4)
print("二叉树2：")
ls = InputInt()
bt2 = BTree()
bt2.CreateBTree(ls)
bt2.Traverse(4)