<p>Given a <code>wordlist</code>, we want to implement a spellchecker that converts a query word into a correct word.</p>

<p>For a given <code>query</code> word, the spell checker handles two categories of spelling mistakes:</p>

<ul>
	<li>Capitalization: If the query matches a word in the wordlist (<strong>case-insensitive</strong>), then the query word is returned with the same case as the case in the wordlist.

	<ul>
		<li>Example: <code>wordlist = [&quot;yellow&quot;]</code>, <code>query = &quot;YellOw&quot;</code>: <code>correct = &quot;yellow&quot;</code></li>
		<li>Example: <code>wordlist = [&quot;Yellow&quot;]</code>, <code>query = &quot;yellow&quot;</code>: <code>correct = &quot;Yellow&quot;</code></li>
		<li>Example: <code>wordlist = [&quot;yellow&quot;]</code>, <code>query = &quot;yellow&quot;</code>: <code>correct = &quot;yellow&quot;</code></li>
	</ul>
	</li>
	<li>Vowel Errors: If after replacing the vowels <code>(&#39;a&#39;, &#39;e&#39;, &#39;i&#39;, &#39;o&#39;, &#39;u&#39;)</code> of the query word with any vowel individually, it matches a word in the wordlist (<strong>case-insensitive</strong>), then the query word is returned with the same case as the match in the wordlist.
	<ul>
		<li>Example: <code>wordlist = [&quot;YellOw&quot;]</code>, <code>query = &quot;yollow&quot;</code>: <code>correct = &quot;YellOw&quot;</code></li>
		<li>Example: <code>wordlist = [&quot;YellOw&quot;]</code>, <code>query = &quot;yeellow&quot;</code>: <code>correct = &quot;&quot;</code> (no match)</li>
		<li>Example: <code>wordlist = [&quot;YellOw&quot;]</code>, <code>query = &quot;yllw&quot;</code>: <code>correct = &quot;&quot;</code> (no match)</li>
	</ul>
	</li>
</ul>

<p>In addition, the spell checker operates under the following precedence rules:</p>

<ul>
	<li>When the query exactly matches a word in the wordlist (<strong>case-sensitive</strong>), you should return the same word back.</li>
	<li>When the query matches a word up to capitlization, you should return the first such match in the wordlist.</li>
	<li>When the query matches a word up to vowel errors, you should return the first such match in the wordlist.</li>
	<li>If the query has no matches in the wordlist, you should return the empty string.</li>
</ul>

<p>Given some <code>queries</code>, return a list of words <code>answer</code>, where <code>answer[i]</code> is the correct word for <code>query = queries[i]</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<pre><strong>Input:</strong> wordlist = ["KiTe","kite","hare","Hare"], queries = ["kite","Kite","KiTe","Hare","HARE","Hear","hear","keti","keet","keto"]
<strong>Output:</strong> ["kite","KiTe","KiTe","Hare","hare","","","KiTe","","KiTe"]
</pre><p><strong class="example">Example 2:</strong></p>
<pre><strong>Input:</strong> wordlist = ["yellow"], queries = ["YellOw"]
<strong>Output:</strong> ["yellow"]
</pre>
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= wordlist.length, queries.length &lt;= 5000</code></li>
	<li><code>1 &lt;= wordlist[i].length, queries[i].length &lt;= 7</code></li>
	<li><code>wordlist[i]</code> and <code>queries[i]</code> consist only of only English letters.</li>
</ul>

class Solution {
public:
  unordered_set<string> dict;
  unordered_map<string, string> lower_dict;
  unordered_map<string, string> vowel_dict;
  
  string lower(const string& str) {
    string tmp = str;
    for (char& ch : tmp) ch = tolower(ch);
    return tmp;
  }
  
  string vowel(const string& str) {
    string tmp = str;
    for (char& ch : tmp) {
      if (ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u') ch = '_';
    }
    return tmp;
  }
  
  string query(const string& q) {
    // When the query exactly matches a word in the wordlist (case-sensitive), you should return the same word back.
    if (dict.count(q) > 0) return q;
      
    // When the query matches a word up to capitlization, you should return the first such match in the wordlist.
    int n = q.size();
    
    if (lower_dict.count(lower(q)) > 0) {
      return lower_dict[lower(q)];
    }

    // When the query matches a word up to vowel errors, you should return the first such match in the wordlist.
    if (vowel_dict.count(vowel(lower(q))) > 0) {
      return vowel_dict[vowel(lower(q))];
    }

    // If the query has no matches in the wordlist, you should return the empty string.
    return "";
  }
  
  vector<string> spellchecker(vector<string>& wordlist, vector<string>& queries) {
    dict = unordered_set<string>(wordlist.begin(), wordlist.end());
    
    for (auto& word : wordlist) if (lower_dict.count(lower(word)) == 0) {
      lower_dict[lower(word)] = word;
    }
    
    for (auto& word : wordlist) if (vowel_dict.count(vowel(lower(word))) == 0) {
      vowel_dict[vowel(lower(word))] = word;
    }
    
    vector<string> res;
    
    for (string& q : queries) {
      res.push_back(query(q));
    }
    
    return res;
  }
};
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