Haffman Code

Haffman Code

什么是Haffman编码？以后再说，嘿嘿先上实现。

Python　实现：

在这个实现当中，我们并没有统计文本的字符出现频率，仅仅是为Haffman Coding的一个demo.

"""Code writer : EOFCode file   : haffman.pyCode date   : 2015.01.28e-mail      : [e-mail] description:    Here is a implementation of Haffman-Codein Python."""class node() :    def __init__(self,num) :        self.right = None        self.left  = None        self.key   = numclass haffman_tree():    def __init__(self, array) :        self.forest = []        for i in range(0, len(array)) :            self.forest += [node(array[i])]        self.build()    def small_tree(self) :        smallest_tree = self.forest[0]        location = 0        for i in range(1, len(self.forest)) :            if self.forest[i].key < smallest_tree.key :                location = i        return location    def delete_root(self, x) :        for i in range(0, len(self.forest)) :            if x.key is self.forest[i].key :               del self.forest[i]               return    def build(self) :        while len(self.forest) is not 1 :            small_tree_1 = self.forest[self.small_tree()]    self.delete_root(small_tree_1)    small_tree_2 = self.forest[self.small_tree()]    self.delete_root(small_tree_2)    tmp_node = node(small_tree_1.key + small_tree_2.key)    tmp_node.right = small_tree_1    tmp_node.left  = small_tree_2    self.forest += [tmp_node]        self.root = self.forest[0]        self.coding(self.root,'')    def coding(self, node, path) :        if node.right is None and node.left is None :            print path, "is the haffman code of", node.key            return        else :            self.coding(node.right, path + '1')            self.coding(node.left,  path + '0')            #------------------------------------------------------tree = haffman_tree(['a','b','c','d','e','f','g','h'])

在Haffman树(就是个二叉树)当中, １代表右拐，０代表左拐。

后续会更新，把Haffman code 的原理和用处讲清楚。