华电北风吹
日期：2016-04-02

Trie树，又名前缀树。Trie树的存储结构与B树类似。需要注意的一点是Trie树的节点不保存任何信息，所有的信息都保存在边上。Trie树比较简单，直接上代码吧。

struct TrieNode
{
    int count;
    TrieNode* next[26];
    bool exist;
    TrieNode() :count(0), exist(false);
};

void Insert(TrieNode* root, string word)
{
    TrieNode* node = root;
    for (int i = 0; i < word.length(); i++)
    {
        int id = word[i] - 'a';
        if (node->next[id] == NULL)
        {
            node->next[id] = new TrieNode();
        }
        node = node->next[id];
        node->count += 1;
    }
    node->exist = true;
}

int Search(TrieNode* root, string word)
{
    TrieNode* node = root;
    for (int i = 0; i < word.length(); i++)
    {
        int id = word[i] - 'a';
        node = node->next[id];
        if (node == NULL)
            return 0;
    }
    return node->count;
}

int main(void)
{
    TrieNode* root = new TrieNode();
    int n;
    string s;
    cin >> n;
    for (int i = 0; i < n; i++)
    {
        cin >> s;
        Insert(root, s);
    }
    cin >> n;
    for (int i = 0; i < n; i++)
    {
        cin >> s;
        cout << Search(root, s) << endl;
    }
    return 0;
}