LeetCode 208. Implement Trie (Prefix Tree)

题目

题意：实现一个前缀树

class Trie {
public:
    int map[100005][126];
    int tag[100005][126];
    int num;
    /** Initialize your data structure here. */
    Trie() {
        
        memset(map,0,sizeof(map));
        memset(tag,0,sizeof(tag));
        num=0;
        
        
    }
    
    /** Inserts a word into the trie. */
    void insert(string word) {
        
        Add(word,0,0);
        
    }
    
    void Add(string word,int i,int pos)
    {
        if(i==word.length())
        {
            return;
        }
            
        if(map[pos][word[i]]==0)
        {
            map[pos][word[i]]=++num;
        }
        
        if(i==word.length()-1)
        {
            tag[pos][word[i]]=1;
        }
        
        Add(word,i+1,map[pos][word[i]]);
    }
    
    
    
    /** Returns if the word is in the trie. */
    bool search(string word) {
        
       return SearchWord(word,0,0,1);
        
    }
    
    bool SearchWord(string word,int i,int pos,int t)
    {
        if(i==word.length())
            return false;
       
        if(map[pos][word[i]]==0)
        {
            return false;
        }
        else
        {
            if(i==word.length()-1)
            {
                if(t==1&&tag[pos][word[i]]==1)
                    return true;
                if(t==0)
                    return true;
            }
            
            return SearchWord(word,i+1,map[pos][word[i]],t);
        }
    }
    
    /** Returns if there is any word in the trie that starts with the given prefix. */
    bool startsWith(string prefix) {
        return SearchWord(prefix,0,0,0);
    }
};

/**
 * 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);
 */