字典树（指针版） 

 1 #include <iostream>
 2 #include <string>
 3 using namespace std;
 4 #define ALPHABET_SIZE 26
 5 
 6 typedef struct trie_node
 7 {
 8     int count;   // 记录该节点代表的单词的个数
 9     trie_node *children[ALPHABET_SIZE]; // 各个子节点 
10 }*trie;
11 
12 trie_node* create_trie_node()
13 {
14     trie_node* pNode = new trie_node();
15     pNode->count = 0;
16     for(int i=0; i<ALPHABET_SIZE; ++i)
17         pNode->children[i] = NULL;
18     return pNode;
19 }
20 
21 void trie_insert(trie root, char* key)
22 {
23     trie_node* node = root;
24     char* p = key;
25     while(*p)
26     {
27         if(node->children[*p-'a'] == NULL)
28         {
29             node->children[*p-'a'] = create_trie_node();
30         }
31         node = node->children[*p-'a'];
32         ++p;
33     }
34     node->count += 1;
35 }
36 /*
37     查询：不存在返回0，存在返回出现的次数
38 */
39 int trie_search(trie root, char* key)
40 {
41     trie_node* node = root;
42     char* p = key;
43     while(*p && node!=NULL)
44     {
45         node = node->children[*p-'a'];
46         ++p;
47     }
48     if(node == NULL)
49         return 0;
50     else
51         return node->count;
52 }
53 
54 int main()
55 {
56     // 关键字集合
57     char keys[][8] = {"the", "a", "there", "answer", "any", "by", "bye", "their"};
58     trie root = create_trie_node();
59     // 创建trie树
60     for(int i = 0; i < 8; i++)
61         trie_insert(root, keys[i]);
62     // 检索字符串
63     char s[][32] = {"Present in trie", "Not present in trie"};
64     printf("%s --- %s\n", "the", trie_search(root, "the")>0?s[0]:s[1]);
65     printf("%s --- %s\n", "these", trie_search(root, "these")>0?s[0]:s[1]);
66     printf("%s --- %s\n", "their", trie_search(root, "their")>0?s[0]:s[1]);
67     printf("%s --- %s\n", "thaw", trie_search(root, "thaw")>0?s[0]:s[1]);
68     return 0;
69 }

 

posted @ 2018-04-13 10:52  痞子熊  阅读(304)  评论(0)    收藏  举报