python学习——二叉树遍历

import os,sys

class node:
    def __init__(self,item):
        self.num=item
        self.lchild=None
        self.rchild=None

class tree:
    def __init__(self):
        self.root=None

    def add(self,ii):
        inode = node(ii)
        if self.root is None:
            self.root=inode
        else:
            p=[self.root]
            iipp=0
            while 1:
                ip=p[iipp]
                #print ip
                iipp=iipp+1
                if ip.lchild is None:
                    ip.lchild=inode
                    return
                elif ip.rchild is None:
                    ip.rchild = inode
                    return
                else:
                    p.append(ip.lchild)
                    p.append(ip.rchild)

    def lorder(self,node1):
        l=[]
        if node1 is not None:
            l.append(node1.num)
            ll= self.lorder(node1.lchild)
            l=l+ll
            #l.append(ll)#带结构
            rl = self.lorder(node1.rchild)
            #l.append(rl)#带结构
            l=l+rl
        return l

    def morder(self,node2):
        m = []
        if node2 is not None:
            lm = self.morder(node2.lchild)
            m = m + lm
            m.append(node2.num)
            rm = self.morder(node2.rchild)
            m = m + rm
        return m

    def rorder(self,node3):
        r = []
        if node3 is not None:
            lr = self.rorder(node3.lchild)
            r = r + lr
            rr = self.rorder(node3.rchild)
            r = r + rr
            r.append(node3.num)
        return r

if __name__ == '__main__':
    t=tree()
    for i in range(1,10):
        t.add(i)
    print t.lorder(t.root)#先序遍历
    print t.morder(t.root)#中序遍历
    print t.rorder(t.root)#后序遍历