LeetCode|Implement Trie (Prefix Tree)

Implement Trie (Prefix Tree)

Implement a trie with insert, search, and startsWith methods.

Note:
You may assume that all inputs are consist of lowercase letters a-z.

class TrieNode {public:    // Initialize your data structure here.    TrieNode() {        memset(next, NULL, sizeof(next));        someWordEndHere = false;    }    TrieNode* next[26];    bool someWordEndHere;};class Trie {public:    Trie() {        root = new TrieNode();    }    // Inserts a word into the trie.    void insert(string word) {        int len = word.length();        TrieNode *p = root;        for(int i = 0; i < len; i++){            int id = word[i]-'a';            if(p->next[id] == NULL){                p->next[id] = new TrieNode();            } p = p->next[id];        } p->someWordEndHere = true;    }    // Returns if the word is in the trie.    bool search(string word) {        int len = word.length();        TrieNode *p = root;        for(int i = 0; i < len; i++){            int id = word[i]-'a';            if(p->next[id] == NULL) return false;            p = p->next[id];        } return p->someWordEndHere;    }    // Returns if there is any word in the trie    // that starts with the given prefix.    bool startsWith(string prefix) {        int len = prefix.length();        TrieNode *p = root;        for(int i = 0; i < len; i++){            int id = prefix[i]-'a';            if(p->next[id] == NULL) return false;            p = p->next[id];        } return true;    }private:    TrieNode* root;};// Your Trie object will be instantiated and called as such:// Trie trie;// trie.insert("somestring");// trie.search("key");