Trie (dictionary tree)

Each node store can be mapped with a hash Map<Character, Trie> map,
You can also use arrays Trie[] children

class Trie {
    

    private Map<Character, Trie> map;
    private boolean endFlag;
    public Trie() {
    
        map = new HashMap<>();
        endFlag = false;
    }
    
    public void insert(String word) {
    
        Trie node = this;
        for(int i = 0; i < word.length(); i++) {
    
            if(!node.map.containsKey(word.charAt(i))) {
    
                Trie tmp = new Trie();
                node.map.put(word.charAt(i), tmp);
            }
                node = node.map.get(word.charAt(i));
        }
        node.endFlag = true;
    }
    
    public boolean search(String word) {
    
        Trie node = this;
        for(int i = 0; i < word.length(); i++) {
    
            if(node.map.containsKey(word.charAt(i))) {
    
                node = node.map.get(word.charAt(i));
            } else {
    
                return false;
            }
        }
        return node.endFlag == true ? true : false;
    }
    
    public boolean startsWith(String prefix) {
    
        Trie node = this;
         for(int i = 0; i < prefix.length(); i++) {
    
            if(node.map.containsKey(prefix.charAt(i))) {
    
                node = node.map.get(prefix.charAt(i));
            } else {
    
                return false;
            }
        }
        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); */