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53class Trie {
class TrieNode{
TrieNode[] children=new TrieNode[26];
boolean isWordEnd;
}
TrieNode root;
/** Initialize your data structure here. */
public Trie() {
root=new TrieNode();
}
/** Inserts a word into the trie. */
public void insert(String word) {
TrieNode p=root;
for(char ch:word.toCharArray()){
int idx=ch-'a';
if(p.children[idx]==null) p.children[idx]=new TrieNode();
p=p.children[idx];
}
p.isWordEnd=true;
}
/** Returns if the word is in the trie. */
public boolean search(String word) {
TrieNode p=root;
for(char ch:word.toCharArray()){
int idx=ch-'a';
if(p.children[idx]==null) return false;
p=p.children[idx];
}
return p!=null&&p.isWordEnd;
}
/** Returns if there is any word in the trie that starts with the given prefix. */
public boolean startsWith(String prefix) {
TrieNode p=root;
for(char ch:prefix.toCharArray()){
int idx=ch-'a';
if(p.children[idx]==null) return false;
p=p.children[idx];
}
return true;
}
}
/**
* Your Trie object will be instantiated and called as such:
* Trie obj = new Trie();
* obj.insert(word);
* boolean param_2 = obj.search(word);
* boolean param_3 = obj.startsWith(prefix);
*/