【leetcode 字典树（前缀树） C++】1032. Stream of Characters

1032. Stream of Characters

class TrieNode {
    
    
public:
    bool is_end;
    vector<TrieNode*> children = vector<TrieNode*>(26, nullptr);
    TrieNode() {
    
     is_end = false; }
};


class StreamChecker {
    
    
public:
    TrieNode* root = new TrieNode();
    TrieNode* p;
    queue<TrieNode*> Q;

    void insert(string word) {
    
    
        p = root;
        for(int ii = 0; ii < word.size(); ii++) {
    
    
            if(!p->children[word[ii] - 'a']) p->children[word[ii] - 'a'] = new TrieNode();
            p = p->children[word[ii] - 'a'];
        }
        p->is_end = true;
    }

    StreamChecker(vector<string>& words) {
    
    
        for(auto &word : words) insert(word);
    }
    
    bool query(char letter) {
    
    
        bool flag = false;
        int Q_len = Q.size();
        for(int ii = 0; ii < Q_len; ii++) {
    
    
            p = Q.front();
            Q.pop();
            if(p->children[letter - 'a']) {
    
    
                Q.push(p->children[letter - 'a']);
                if(p->children[letter - 'a']->is_end) flag = true;
            }
        }
        if(root->children[letter - 'a']) {
    
    
            Q.push(root->children[letter - 'a']);
            if(root->children[letter - 'a']->is_end) flag = true;
        }
        return flag;
    }
};

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