1032

class Trie {
private:
    bool end;
    Trie* children[26];
public:
    /** Initialize your data structure here. */
    Trie() {
        end = false;
        for(int i=0; i<26; i++)
            children[i] = NULL;
    }

    /** Inserts a word into the trie. */
    void insert(string word) {
        Trie *node = this;
        for(char c: word){
            c -= 'a';
            if(!node->children[c])
                node->children[c] = new Trie();
            node = node->children[c];
        }
        node->end = true;
    }

    /** Returns if there is any word in the trie that starts with the given prefix. */
    bool startsWith(vector<char> prefix) {
        Trie *node = this;
        for(char c: prefix){
            c -= 'a';
            if(!node->children[c])
                return false;
            node = node->children[c];
            if(node->end) return true;
        }
        return false;
    }
};

class StreamChecker {
public:
    vector<char> str;
    Trie *root;
    int longLen = 0;
    StreamChecker(vector<string>& words) {
        root = new Trie();
        for(auto &word: words){
            longLen = max(longLen, int(word.length()));
            reverse(word.begin(), word.end());
            root->insert(word);
        }
    }

    bool query(char letter) {
        str.insert(str.begin(), letter);
        if(str.size() > longLen)
            str.pop_back();
        if(root->startsWith(str))
            return true;
        return false;
    }
};

/**
 * Your StreamChecker object will be instantiated and called as such:
 * StreamChecker* obj = new StreamChecker(words);
 * bool param_1 = obj->query(letter);
 */