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ImplementTrie.java
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74 lines (62 loc) · 1.93 KB
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class TrieNode {
char val;
Map<Character, TrieNode> dict;
boolean isLeaf;
TrieNode(char v, boolean b) {
this.val = v;
this.isLeaf = b;
this.dict = new HashMap<>();
}
}
class Trie {
TrieNode root;
/** Initialize your data structure here. */
public Trie() {
this.root = new TrieNode('\0', true);
}
/** Inserts a word into the trie. */
public void insert(String word) {
TrieNode curr = root;
for (int i = 0; i < word.length(); i++) {
char currChar = word.charAt(i);
if (!curr.dict.containsKey(currChar)) {
curr.dict.put(currChar, new TrieNode(currChar, false));
}
curr = curr.dict.get(currChar);
if (i == word.length() - 1) {
curr.isLeaf = true;
}
}
}
/** Returns if the word is in the trie. */
public boolean search(String word) {
TrieNode curr = root;
for (int i = 0; i < word.length(); i++) {
char currChar = word.charAt(i);
if (!curr.dict.containsKey(currChar)) {
return false;
}
curr = curr.dict.get(currChar);
}
return curr.isLeaf;
}
/** Returns if there is any word in the trie that starts with the given prefix. */
public boolean startsWith(String prefix) {
TrieNode curr = root;
for (int i = 0; i < prefix.length(); i++) {
char currChar = prefix.charAt(i);
if (!curr.dict.containsKey(currChar)) {
return false;
}
curr = curr.dict.get(currChar);
}
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);
*/