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| class WordDictionary {
Trie trie;
public WordDictionary() {
trie = new Trie();
}
public void addWord(String word) {
trie.add(word);
}
public boolean search(String word) {
return dfs(word, 0, trie);
}
private boolean dfs(String word, int index, Trie node) {
if (index == word.length()) return node.isEnd;
char c = word.charAt(index);
if (c == '.') {
for (int i = 0; i < 26; ++i) {
Trie child = node.next[i];
if (child != null && dfs(word, index + 1, child)) {
return true;
}
}
} else {
int u = c - 'a';
Trie child = node.next[u];
if (child != null && dfs(word, index + 1, child)) {
return true;
}
}
return false;
}
private static class Trie {
Trie[] next;
boolean isEnd;
public Trie() {
next = new Trie[26];
isEnd = false;
}
public void add(String word) {
Trie node = this;
for (int i = 0; i < word.length(); ++i) {
int u = word.charAt(i) - 'a';
if (node.next[u] == null) {
node.next[u] = new Trie();
}
node = node.next[u];
}
node.isEnd = true;
}
}
}
|
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