Trie 树

Trie 树主要是Insert 和search

题目： hoj 前缀查询：
直接上对应的代码吧：

class TriNode
{
public:
    TriNode();
    ~TriNode();

public:
    int Count;
    TriNode *next[26];
    bool exist;
};

TriNode::TriNode()
{
    Count = 0;
    //memset(next, 0, sizeof(next));
    exist = false;
}

void trieInsert(TriNode *root, char *word)
{
    TriNode *node  = root;
    char *p = word;
    int id;
    while(*p != '\0' && p != nullptr)
    {
        id = (*p) - 'a';
        if(node->next[id] == nullptr)
        {
            node->next[id] = new TriNode();
        }
        node = node->next[id];
        ++p;
        (node->Count)++;
    }
    node->exist = true;
}

int trieSearch(TriNode *root, char *word)
{
    TriNode *node = root;
    char *p = word;
    int id;
    if(node == nullptr)
    {
        return 0;
    }
    while(*p)
    {
        id = *p - 'a';
        node = node->next[id];
        ++p;
        if(node == nullptr)
        {
            return 0;
        }
    }
    return node->Count;
}

int main()
{
    TriNode *root = new TriNode();
    char str[12];
    bool flag = false;
    while(gets(str))
    {
        if(flag)
        {
            cout << trieSearch(root, str) << endl;
        }
        else
        {
            if(strlen(str) != 0)
            {
                trieInsert(root, str);
            }
            else
            {
                flag = true;
            }
        }
    }
    return 0;

}