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# 211. Add and Search Word Data structure design

## problem description

Design a data structure that supports the following two operations:

void addWord(word) bool search(word) search(word) can search a literal word or a regular expression string containing only letters a-z or .. A . means it can represent any one letter.

**Example:**

```
addWord("bad")
addWord("dad")
addWord("mad")
search("pad") -> false
search("bad") -> true
search(".ad") -> true
search("b..") -> true
Note:
You may assume that all words are consist of lowercase letters a-z.
```

## algorithm thought

这题直接用字典树解决即可，接口和这题都差不多。\[208. Implement Trie (Prefix Tree)]\(208.-Implement-Trie-(Prefix-Tree).md)