python-哈夫曼树

  #!/usr/bin/python
 #coding=utf-8
 #哈夫曼树创建

 class Node():
     def __init__(self,value,left=None,right=None):
         self.value=value
         self.left=left
         self.right=right
 class Halfman():
     def init(self,k):
         k.sort()
        # key=Node(k[0])
         self.root=Node(k[0])
         if len(k)==len(set(k)):  #无重复项判定
             for i in range(1,len(k)):
                 node=Node(k[i])
                 if i==1:
                     max=k[i]*(len(k)-i)+self.root.value*(len(k)-1)
                 else:
                     max=k[i]*(len(k)-i)+self.root.value
                 root=Node(max,self.root,node)
                 self.root=root
             return self.root
     def pre(self,root):
         if root==None:return
         print root.value
         self.pre(root.left)
         self.pre(root.right)

 k=[2,8,5,6,4,7,9,1,3]
 tree=Halfman()
 a=tree.init([2,8,5,6,4,7,9,1,3])

 tree.pre(a)

 print '*'*40

 print a.value
 print a.left.value
 print a.right.value