python學習——二叉樹遍歷

import os,sysclass node:    def __init__(self,item):        self.num=item        self.lchild=None        self.rchild=Noneclass 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)#帶結構            rl = self.lorder(node1.rchild)            #l.append(rl)#帶結構            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 rif __name__ == '__main__':    t=tree()    for i in range(1,10):        t.add(i)    print t.lorder(t.root)#先序遍歷    print t.morder(t.root)#中序遍歷    print t.rorder(t.root)#後序遍歷