LeetCode 208. 实现 Trie (前缀树)

原题目：https://leetcode-cn.com/problems/implement-trie-prefix-tree/

 

思路：

看一下youtube上的视频：视频

举个栗子：see,sells,she

 

 

代码：

class Trie {
private:
    bool isEnd;
    Trie* next[26];
public:
    /** Initialize your data structure here. */
    Trie() {
        isEnd = false;
        memset(next,0,sizeof(next));
    }
    
    /** Inserts a word into the trie. */
    void insert(string word) {
        auto 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;
    }
    
    /** Returns if the word is in the trie. */
    bool search(string word) {
        auto node = this;
        for(char& c: word){
            node = node->next[c-'a'];
            if(node==NULL) return false;
        }
        return node->isEnd;
    }
    
    /** Returns if there is any word in the trie that starts with the given prefix. */
    bool startsWith(string prefix) {
        auto node = this;
        for(char& c:prefix){
            node = node->next[c-'a'];
            if(node==NULL) return false;
        }
        return true;
    }
};