btree.py

#!/usr/bin/env python
# encoding: utf-8
# author: Lock
# time: 2018/1/24 00:38
class BTree:
    def __init__(self, value):
        self.left = None
        self.data = value
        self.right = None

    def insertLeft(self, value):
        self.left = BTree(value)
        return self.left

    def insertRight(self, value):
        self.right = BTree(value)
        return self.right

    def show(self):
        print self.data,


def preorder(node):
    if node.data:
        node.show()
        if node.left:
            preorder(node.left)
        if node.right:
            preorder(node.right)


def inorder(node):
    if node.data:
        if node.left:
            inorder(node.left)
        node.show()
        if node.right:
            inorder(node.right)


def postorder(node):
    if node.data:
        if node.left:
            postorder(node.left)
        if node.right:
            postorder(node.right)
        node.show()


def layerorder(node):
    stack = [node]
    while len(stack):
        	node = stack.pop(0)
        	if node.data:
        		node.show()
	        if node.left:
	            stack.append(node.left)
	        if node.right:
	        	stack.append(node.right)


if __name__ == "__main__":
    Root = BTree("root")
    A = Root.insertLeft("A")
    C = A.insertLeft("C")
    D = C.insertRight("D")
    F = D.insertLeft("F")
    G = D.insertRight("G")
    B = Root.insertRight("B")
    E = B.insertRight("E")

    print "前序遍历：",
    preorder(Root)

    print ""
    print "中序遍历：",
    inorder(Root)

    print ""
    print "后序遍历：",
    postorder(Root)

    print ""
    print "层序遍历：",
    layerorder(Root)