trie树 python trie树python代码

Trie树 不解析，  本园很多博文有提到。 

 

直接上代码：

 

#coding:utf-8
'''
create on 2013-07-30
@author :HuangYanQiang
'''
LETTER_NUM=27;#组成单词的字母个数，26个字母+'-'

#Trie 结构体
class Node:
    def __init__(self, is_word=False):
        global LETTER_NUM;
        self.is_word = is_word;#是不是单词结束节点
        self.prefix_count = 0;#这个前缀的单词个数
        self.children = [None for child in range(LETTER_NUM)];
        
#Trie 结构体
class Trie:
    def __init__(self):
        self.head = Node();
    ###插入新单词
    def insert(self, word):
        current = self.head;
        count = 0 ;
        
        for letter in word:
            if (letter == '-'):
                int_letter=LETTER_NUM-1;
            else:
                int_letter = ord(letter)-ord('a');
            if(current.children[int_letter] is None):
                current.children[int_letter] = Node();
                current = current.children[int_letter];
                count += 1;
                current.prefix_count = count;
            else:
                current = current.children[int_letter];
                current.prefix_count += 1;
        current.is_word = True;
    ###查询单词是否存在
    def search(self, word):
        current = self.head;
        int_letter = 0;
        for letter in word:
            if (letter == '-'):
                int_letter=LETTER_NUM-1;
            else:
                int_letter = ord(letter)-ord('a');

            if (current.children[int_letter] is None):
                #print "int_letter = " + str(int_letter);
                return False;
            else:
                current = current.children[int_letter];
        return current.is_word;
    ###根据字母前缀输出所有的单词
    def output(self,strPrefix):
        if(strPrefix is None or strPrefix == ""):
            print ("please tell me prefix letter.");
        currentNode = self.head;
        int_letter = 0;
        for letter in strPrefix:
            if (letter == '-'):
                int_letter=LETTER_NUM-1;
            else:
                int_letter = ord(letter)-ord('a');
            currentNode = currentNode.children[int_letter];
            
        if(currentNode is not None):
            if(currentNode.is_word):
                print (strPrefix+"; ");
        else:
            return;
            
        for i in range(LETTER_NUM):
            if(currentNode.children[i] is not None):
                self.output(strPrefix+chr(i+ord('a')));
            
        #################    

###读取单词列表文本构造Trie结构
class BuildTrie:

    def __init__(self):
        self.trie = Trie();
        for line in file("EnglishDict.txt"):
            line = line.lower();#全部换成小写
            line = line.replace('\r','').replace('\n','');#去掉结束符
            isword = True;
            int_letter = 0;
            str_letter="abcdefghijklmnopqrstuvwxyz-ABCDEFGHIJKLMNOPQRSTUVWXYZ"
            for letter in line:
                if(letter not in str_letter ):
                    isword = False;
                    break;
            if(isword == False):
                print (line + ", it is not a word");
                continue;
            else:
                self.trie.insert(line);



if __name__=="__main__":
    import doctest
    doctest.testmod();
    
    
#    t = Trie();
#    t.insert("apple");
#    t.insert("abc");
#    t.insert("abandon");
#    t.insert("bride");
#    t.insert("bridegroom");
#    t.insert("good");
#    t.output("b");
    
    
    bt = BuildTrie();
    t = bt.trie
    t.output("z");
    
    
    print t.search("apple");
    print t.search("fff");
    print t.search("good");
    print("a num:"+str(t.head.children[0].prefix_count));
    print("ab num:"+str(t.head.children[0].children[1].prefix_count));
    print("b num:"+str(t.head.children[1].prefix_count));