题目：

思路：

tire树，学过，模板题。一种数据结构与算法的结合吧。

 

代码是：

//codeclass Trie {
private:bool isEnd;Trie* next[26];
public:Trie() {isEnd = false;memset(next, 0, sizeof(next));}void insert(string word) {Trie* node = this;for (char c : word) {if (node->next[c-'a'] == NULL) {node->next[c-'a'] = new Trie();}node = node->next[c-'a'];}node->isEnd = true;}bool search(string word) {Trie* node = this;for (char c : word) {node = node->next[c - 'a'];if (node == NULL) {return false;}}return node->isEnd;}bool startsWith(string prefix) {Trie* node = this;for (char c : prefix) {node = node->next[c-'a'];if (node == NULL) {return false;}}return true;}
};