查找元素用map
按照词条搜索，超时，根据solution，用map、hash map更好。

class Solution {
public:
    
    // 只要在此表里，不一定是一一对应的。
    // 规则有先后顺序，完全匹配》差大小写》差原音匹配（原始和替换部分都是原音）》错误
    // 长度一定相同，不然一定是false
    
    bool iscase1(string word, string query){
        for(int i=0;i<word.size();i++){
            if (word[i]!=query[i]){
                return false;
            }
        }
        return true;
    }
    
    bool iscase2(string word, string query){
         for(int i=0;i<word.size();i++){
            if (word[i]!=query[i]){ // remove 'a' 'A' cases
                if (word[i]>='A'&&word[i]<='Z'){
                    word[i] = word[i]-'A'+'a';
                }
                if (query[i]>='A'&&query[i]<='Z'){
                    query[i] = query[i]-'A'+'a';
                }
                if (word[i]!=query[i]){
                    return false;
                }
            }
         }
         return true;
     }
    
    
    bool iscase3(string word, string query){
        for(int i=0;i<word.size();i++){
            if (word[i]!=query[i]){ // remove 'a' 'A' cases
                if (word[i]>='A'&&word[i]<='Z'){
                    word[i] = word[i]-'A'+'a';
                }
                if (query[i]>='A'&&query[i]<='Z'){
                    query[i] = query[i]-'A'+'a';
                }
                if ((word[i]=='a' || word[i]=='e' || word[i]=='i'||word[i]=='o'||word[i]=='u')&&(query[i]=='a' || query[i]=='e' || query[i]=='i'||query[i]=='o'||query[i]=='u')){
                    continue;
                }
                else if (word[i]==query[i]){
                    continue;
                }
                else{
                    return false;
                }
            }
         }
         return true;
    }
    
    int func(string word, string query){
        if (iscase1(word, query)){
            return 1;
        }
        else if (iscase2(word, query)){
            return 2;
        }
        else if (iscase3(word, query)){
            return 3;
        }
        else{
            return 4;
        }
    }
    
    string func2(vector<string>& words, string query){
       
        int min = 4;
        string minwords="";
        for (int i=0;i<words.size();i++){
            int res = func(words[i], query);
            //cout<<words[i]<<" "<<res<<endl;
            if (res<min){
                min = res;
                minwords = words[i];
            }
        }
        
        return minwords;
    }
    
    
    vector<string> spellchecker(vector<string>& wordlist, vector<string>& queries) {
        map<int, vector<string>> len2words;
        for (int i=0;i<wordlist.size();i++){
            int len = wordlist[i].size();
            if (len2words.find(len)!=len2words.end()){
                len2words[len].push_back(wordlist[i]);
            }
            else{
                vector<string> temp(1, wordlist[i]);
                len2words[len] = temp;
            }
        }
        
        vector<string> res;
        for (int i=0;i<queries.size();i++){
            string query = queries[i];
            vector<string> words = len2words[query.size()];
            string temp = func2(words, query);
            res.push_back(temp);
        }
        return res;   
    }
};

采用map、hash map用于查找（针对查找元素是否存在的问题，采用map）

class Solution {
public:
    
    
    
    string tolow(string s){
        for (int i=0;i<s.size();i++){
            if (s[i]>='A'&&s[i]<='Z'){
                s[i] = s[i]-'A'+'a';
            }
        }
        return s;
    }
    
    string removevowel(string s){
        string ss = tolow(s);
        for(int i=0;i<ss.size();i++){
            if (ss[i]=='a'||ss[i]=='e'||ss[i]=='i'||ss[i]=='o'||ss[i]=='u'){
                ss[i]='#';
            }
        }
        return ss;
    }
    
    
    
    vector<string> spellchecker(vector<string>& wordlist, vector<string>& queries) {
        
        map<string, string> map1;
        for (int i=0;i<wordlist.size();i++){
            if (map1.find(wordlist[i])==map1.end()){
                map1[wordlist[i]] = wordlist[i];
            }
        }
        
        map<string, string> map2;
        for (int i=0;i<wordlist.size();i++){
            string temp = tolow(wordlist[i]);
            if (map2.find(temp)==map2.end()){
                map2[temp] = wordlist[i];
            }
        }
        
        map<string, string> map3;
        for (int i=0;i<wordlist.size();i++){
            string temp = removevowel(wordlist[i]);
            if (map3.find(temp)==map3.end()){
                map3[temp] = wordlist[i];
            }
        }
        
        
        
        vector<string> res;
        for (int i=0;i<queries.size();i++){
            string query = queries[i];
            string temp1 = tolow(query);
            string temp2 = removevowel(query);
            if (map1.find(query)!=map1.end()){
                res.push_back(map1[query]);
            }
            else if (map2.find(temp1)!=map2.end()){
                res.push_back(map2[temp1]);
            }
            else if (map3.find(temp2)!=map3.end()){
                res.push_back(map3[temp2]);
            }
            else{
                res.push_back("");
            }
        }
        return res;   
    }
};