请你设计一个数据结构，支持 添加新单词 和 查找字符串是否与任何先前添加的字符串匹配 。
实现词典类 WordDictionary ：
WordDictionary()初始化词典对象void addWord(word)将word添加到数据结构中，之后可以对它进行匹配bool search(word)如果数据结构中存在字符串与word匹配，则返回true；否则，返回false。word中可能包含一些'.'，每个.都可以表示任何一个字母。
示例：
输入：
["WordDictionary","addWord","addWord","addWord","search","search","search","search"]
[[],["bad"],["dad"],["mad"],["pad"],["bad"],[".ad"],["b.."]]
输出：
[null,null,null,null,false,true,true,true]
解释：
WordDictionary wordDictionary = new WordDictionary();
wordDictionary.addWord("bad");
wordDictionary.addWord("dad");
wordDictionary.addWord("mad");
wordDictionary.search("pad"); // 返回 False
wordDictionary.search("bad"); // 返回 True
wordDictionary.search(".ad"); // 返回 True
wordDictionary.search("b.."); // 返回 True
提示：
1 <= word.length <= 25addWord中的word由小写英文字母组成search中的word由 '.' 或小写英文字母组成- 最多调用
104次addWord和search
“前缀树”实现。
class Trie:
def __init__(self):
self.children = [None] * 26
self.is_end = False
class WordDictionary:
def __init__(self):
self.trie = Trie()
def addWord(self, word: str) -> None:
node = self.trie
for c in word:
idx = ord(c) - ord('a')
if node.children[idx] is None:
node.children[idx] = Trie()
node = node.children[idx]
node.is_end = True
def search(self, word: str) -> bool:
def search(word, node):
for i in range(len(word)):
c = word[i]
idx = ord(c) - ord('a')
if c != '.' and node.children[idx] is None:
return False
if c == '.':
for child in node.children:
if child is not None and search(word[i + 1 :], child):
return True
return False
node = node.children[idx]
return node.is_end
return search(word, self.trie)
# Your WordDictionary object will be instantiated and called as such:
# obj = WordDictionary()
# obj.addWord(word)
# param_2 = obj.search(word)class Trie {
Trie[] children = new Trie[26];
boolean isEnd;
}
class WordDictionary {
private Trie trie;
/** Initialize your data structure here. */
public WordDictionary() {
trie = new Trie();
}
public void addWord(String word) {
Trie node = trie;
for (char c : word.toCharArray()) {
int idx = c - 'a';
if (node.children[idx] == null) {
node.children[idx] = new Trie();
}
node = node.children[idx];
}
node.isEnd = true;
}
public boolean search(String word) {
return search(word, trie);
}
private boolean search(String word, Trie node) {
for (int i = 0; i < word.length(); ++i) {
char c = word.charAt(i);
int idx = c - 'a';
if (c != '.' && node.children[idx] == null) {
return false;
}
if (c == '.') {
for (Trie child : node.children) {
if (child != null && search(word.substring(i + 1), child)) {
return true;
}
}
return false;
}
node = node.children[idx];
}
return node.isEnd;
}
}
/**
* Your WordDictionary object will be instantiated and called as such:
* WordDictionary obj = new WordDictionary();
* obj.addWord(word);
* boolean param_2 = obj.search(word);
*/type WordDictionary struct {
root *trie
}
func Constructor() WordDictionary {
return WordDictionary{new(trie)}
}
func (this *WordDictionary) AddWord(word string) {
this.root.insert(word)
}
func (this *WordDictionary) Search(word string) bool {
n := len(word)
var dfs func(int, *trie) bool
dfs = func(i int, cur *trie) bool {
if i == n {
return cur.isEnd
}
c := word[i]
if c != '.' {
child := cur.children[c-'a']
if child != nil && dfs(i+1, child) {
return true
}
} else {
for _, child := range cur.children {
if child != nil && dfs(i+1, child) {
return true
}
}
}
return false
}
return dfs(0, this.root)
}
type trie struct {
children [26]*trie
isEnd bool
}
func (t *trie) insert(word string) {
cur := t
for _, c := range word {
c -= 'a'
if cur.children[c] == nil {
cur.children[c] = new(trie)
}
cur = cur.children[c]
}
cur.isEnd = true
}
/**
* Your WordDictionary object will be instantiated and called as such:
* obj := Constructor();
* obj.AddWord(word);
* param_2 := obj.Search(word);
*/class trie {
public:
vector<trie*> children;
bool is_end;
trie() {
children = vector<trie*>(26, nullptr);
is_end = false;
}
void insert(const string& word) {
trie* cur = this;
for (char c : word) {
c -= 'a';
if (cur->children[c] == nullptr) {
cur->children[c] = new trie;
}
cur = cur->children[c];
}
cur->is_end = true;
}
};
class WordDictionary {
private:
trie* root;
public:
WordDictionary()
: root(new trie) { }
void addWord(string word) {
root->insert(word);
}
bool search(string word) {
return dfs(word, 0, root);
}
private:
bool dfs(const string& word, int i, trie* cur) {
if (i == word.size()) {
return cur->is_end;
}
char c = word[i];
if (c != '.') {
trie* child = cur->children[c - 'a'];
if (child != nullptr && dfs(word, i + 1, child)) {
return true;
}
} else {
for (trie* child : cur->children) {
if (child != nullptr && dfs(word, i + 1, child)) {
return true;
}
}
}
return false;
}
};
/**
* Your WordDictionary object will be instantiated and called as such:
* WordDictionary* obj = new WordDictionary();
* obj->addWord(word);
* bool param_2 = obj->search(word);
*/