208. 实现 Trie (前缀树) 

 1 //所有实现最好写在一个类中
 2 class Trie 
 3 {
 4 public:
 5     bool is_end;   //是否以该单词结尾
 6     Trie* son[26]; //该节点儿子的个数
 7     Trie()
 8     {
 9         is_end = false;
10         for(int i = 0;i < 26;i ++) son[i] = NULL;
11     }
12     
13     /** Inserts a word into the trie. */
14     void insert(string word) 
15     {
16         auto p = this;
17         for(auto c : word) 
18         {
19             int u = c - 'a';
20             if(p->son[u] == NULL) p->son[u] = new Trie();
21             p = p->son[u];
22         }
23         p->is_end = true;
24     }
25     
26     /** Returns if the word is in the trie. */
27     bool search(string word) 
28     {
29         auto p = this;
30         for(auto c : word) 
31         {
32             int u = c - 'a';
33             if(p->son[u] == NULL) return false;
34             p = p->son[u];
35         }
36         return p->is_end;
37     }
38     
39     /** Returns if there is any word in the trie that starts with the given prefix. */
40     bool startsWith(string prefix) 
41     {
42         auto p = this;
43         for(auto c : prefix) 
44         {
45             int u = c - 'a';
46             if(p->son[u] == NULL) return false;
47             p = p->son[u];
48         }
49         return true;
50     }
51 };

 

posted @ 2020-03-24 19:07  Jinxiaobo0509  阅读(141)  评论(0)    收藏  举报