trie

struct  {
    bool end = false;
    vector<TrieNode*> alpha;
    TrieNode(){
        alpha = vector<TrieNode*>(26, NULL);
    }
};

class Trie {
public:
    TrieNode* root;
    
    Trie() {
        root = new TrieNode();
    }

    /** Inserts a word into the trie. */
    void insert(string word) {
        TrieNode* temp = root;
        for(int i = 0; i < word.length(); i++){
            int cind = word[i] - 'a';
            if(!temp->alpha[cind]){
                temp->alpha[cind] = new TrieNode();
            }
            temp = temp->alpha[cind];
        }
        temp->end = true;
    }

    /** Returns if the word is in the trie. */
    bool search(string word) {
        TrieNode* temp = root;
        for(char c : word){
            int cind = c - 'a';
            if(!temp->alpha[cind])
                return false;
            temp = temp->alpha[cind];
        }
        if(!temp->end)
            return false;

        return true;
    }

    /** Returns if there is any word in the trie that starts with the given prefix. */
    bool startsWith(string prefix) {
        TrieNode* temp = root;
        for(char c : prefix){
            int cind = c - 'a';
            if(!temp->alpha[cind])
                return false;
            temp = temp->alpha[cind];
        }
        return true;
    }
};