Implement a trie with insert, search, and startsWith methods.
Note:
You may assume that all inputs are consist of lowercase letters a-z.
实现字典树，包括插入、查询整词、查询前缀的函数。
代码语言：javascript复制class node
{
public:
int flag;
node* next[26];
node(int x = 0)
{
flag = x;
memset(next, 0, sizeof(next));
}
};
class Trie {
public:
/** Initialize your data structure here. */
node* root;
Trie() {
root = new node();
}
/** Inserts a word into the trie. */
void insert(string word)
{
node* p = root;
for(int i = 0; i < word.size(); i )
{
if(!p->next[word[i] - 'a']) p->next[word[i] - 'a'] = new node();
p = p->next[word[i] - 'a'];
}
p->flag = 1;
}
/** Returns if the word is in the trie. */
bool search(string word)
{
node* p = root;
for(int i = 0; i < word.size(); i )
{
if(!p->next[word[i] - 'a']) return false;
p = p->next[word[i] - 'a'];
}
return p->flag == 1;
}
/** Returns if there is any word in the trie that starts with the given prefix. */
bool startsWith(string prefix)
{
node* p = root;
for(int i = 0; i < prefix.size(); i )
{
if(!p->next[prefix[i] - 'a']) return false;
p = p->next[prefix[i] - 'a'];
}
return true;
}
};
/**
* Your Trie object will be instantiated and called as such:
* Trie obj = new Trie();
* obj.insert(word);
* bool param_2 = obj.search(word);
* bool param_3 = obj.startsWith(prefix);
*/
