966. Vowel Spellchecker

Given a wordlist, we want to implement a spellchecker that converts a query word into a correct word.

For a given query word, the spell checker handles two categories of spelling mistakes:

• Capitalization: If the query matches a word in the wordlist (case-insensitive), then the query word is returned with the same case as the case in the wordlist.

• Example: wordlist = [“yellow”], query = “YellOw”: correct = “yellow”
• Example: wordlist = [“Yellow”], query = “yellow”: correct = “Yellow”
• Example: wordlist = [“yellow”], query = “yellow”: correct = “yellow”

• Vowel Errors: If after replacing the vowels (‘a’, ‘e’, ‘i’, ‘o’, ‘u’) of the query word with any vowel individually, it matches a word in the wordlist (case-insensitive), then the query word is returned with the same case as the match in the wordlist.

• Example: wordlist = [“YellOw”], query = “yollow”: correct = “YellOw”
• Example: wordlist = [“YellOw”], query = “yeellow”: correct = “” (no match)
• Example: wordlist = [“YellOw”], query = “yllw”: correct = “” (no match)

In addition, the spell checker operates under the following precedence rules:

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

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

class Solution {
    public String[] spellchecker(String[] wordlist, String[] queries) {
        Set<String> wordSet = new HashSet<>();
        Map<String, String> vowelMap = new HashMap<>();
        Map<String, String> wordMap = new HashMap<>();
        for(String word : wordlist) {
            wordSet.add(word);
            wordMap.putIfAbsent(word.toLowerCase(), word);
            vowelMap.putIfAbsent(convert(word.toLowerCase()), word);
        }

        String[] res = new String[queries.length];
        for(int idx = 0; idx < queries.length; idx++) {
            if(wordSet.contains(queries[idx])) {
                res[idx] = queries[idx];
            } else if(wordMap.containsKey(queries[idx].toLowerCase())) {
                res[idx] = wordMap.get(queries[idx].toLowerCase());
            } else if(vowelMap.containsKey(convert(queries[idx].toLowerCase()))) {
                res[idx] = vowelMap.get(convert(queries[idx].toLowerCase()));
            } else {
                res[idx] = "";
            }
        }

        return res;
    }

    private String convert(String s) {
        StringBuilder sb = new StringBuilder();
        for(int i = 0; i < s.length(); i++) {
            switch (s.charAt(i)) {
                case 'a':
                case 'e':
                case 'i':
                case 'o':
                case 'u':
                    sb.append("*"); break;
                default:
                    sb.append(s.charAt(i)); break;
            }
        }
        return sb.toString();
    }
}