062. 實現字首樹

class Trie {
public:
    /** Initialize your data structure here. */

    int son[100010][26],cnt[100010],idx=0;
    Trie() {
        memset(son,0,sizeof son);
    }
    
    /** Inserts a word into the trie. */
    void insert(string word) {
        int p=0;
        for( char c: word)
        {
           int u=c-'a';
           if(!son[p][u])son[p][u]=++idx;
           p=son[p][u];
        }
        cnt[p]++;
    }
    
    /** Returns if the word is in the trie. */
    bool search(string word) {
        int p=0;
        for(char c:word){
            int u=c-'a';
            if(!son[p][u])return false;
            p=son[p][u];
        }
        return cnt[p]>0;

    }
    
    /** Returns if there is any word in the trie that starts with the given prefix. */
    bool startsWith(string prefix) {
         int p=0;
        for(char c:prefix){
            int u=c-'a';
            if(!son[p][u])return false;
            p=son[p][u];
        }
        return true;
    }
};
 

063. 替換單詞

class Solution {
public:
    int son[100010][26],cnt[100010],idx=0;
    void insert(string s)
    {
        int p=0;
        for(char c:s)
        {
            int u=c-'a';
            if(!son[p][u])son[p][u]=++idx;
            p=son[p][u];
        }
        cnt[p]++;
    }
    string check(string s)
    {
        string res;
        int p=0;
        for(char c:s)
        {
            int u=c-'a';
            if(!son[p][u])break;
            res+=c;
            p=son[p][u];
            if(cnt[p])return res;
        }
        if(cnt[p])return res;
        return "";

    }
    string replaceWords(vector<string>& dictionary, string sentence) {
        for(auto s:dictionary)insert(s);
         stringstream ssin(sentence);
         string ans,word;
         while(ssin >>word)
         {
             //cout<<word<<"..."<<endl;
             string x=check(word);
           //  cout<<x<<endl;
             
             if(x!="")
             {
                 ans+=x;
             }
             else ans+=word;
             ans+=" ";
         }
         return ans.substr(0,ans.size()-1);

    }
};