LeetCode Implement Trie (Prefix Tree) （实现trie树3个函数：插入，查找，前缀）

题意：实现trie树的3个功能，只含小写字母的串。

思路：老实做即可！

 class TrieNode {
 public:
     TrieNode*  chd[];
     bool flag;
     // Initialize your data structure here.
     TrieNode() {
         memset(chd,,sizeof(chd));
         flag=;
     }

 };

 class Trie {
 public:
     Trie() {
         root = new TrieNode();
     }

     // Inserts a word into the trie.
     void insert(string word) {
         int p=;
         TrieNode* tmp=root;
         while(p<word.size())
         {
             if(!tmp->chd[word[p]-'a'])
             {
                 TrieNode* newnode=new TrieNode();
                 tmp->chd[word[p]-'a']=newnode;
             }
             tmp=tmp->chd[word[p]-'a'];
             p++;
         }
         tmp->flag=;
     }

     // Returns if the word is in the trie.
     bool search(string word) {
         int p=;
         TrieNode* tmp=root;
         while(p<word.size())
         {
             //cout<<word[p]<<" ";
             if(tmp->chd[word[p]-'a'])    tmp=tmp->chd[word[p]-'a'];
             else return false;
             p++;
         }
         if(tmp->flag==) return true;
         return false;
     }

     // Returns if there is any word in the trie
     // that starts with the given prefix.
     bool startsWith(string prefix) {
         int p=;
         TrieNode* tmp=root;
         while(p<prefix.size())
         {
             if(tmp->chd[prefix[p]-'a'])    tmp=tmp->chd[prefix[p]-'a'];
             else return false;
             p++;
         }
         return true;
     }

 private:
     TrieNode* root;
 };

AC代码