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Day-14-implementTrie.java
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Day-14-implementTrie.java
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class Trie {
class TrieNode{
static final int ALPHABET_SIZE=26;
TrieNode[] child = new TrieNode[ALPHABET_SIZE];
boolean isEnd;
}
TrieNode root;
/** Initialize your data structure here. */
public Trie() {
root = new TrieNode();
}
/** Inserts a word into the trie. */
public void insert(String word) {
char[] data = word.toCharArray();
TrieNode tempNode = root;
for(char c : data){
int index = c - 'a';
if(tempNode.child[index] == null)
tempNode.child[index] = new TrieNode();
tempNode = tempNode.child[index];
}
tempNode.isEnd = true;
}
/** Returns if the word is in the trie. */
public boolean search(String word) {
char[] data = word.toCharArray();
TrieNode tempNode = root;
for (char c : data) {
int index = c - 'a';
if (tempNode.child[index] == null) {
return false;
}
tempNode = tempNode.child[index];
}
if (tempNode != null && tempNode.isEnd == false) {
return false;
}
return true;
}
/** Returns if there is any word in the trie that starts with the given prefix. */
public boolean startsWith(String prefix) {
char[] data = prefix.toCharArray();
TrieNode tempNode = root;
for (char c : data) {
int index = c - 'a';
if (tempNode.child[index] == null) {
return false;
}
tempNode = tempNode.child[index];
}
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);
*/