0966. Vowel Spellchecker (M)

题目

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].

Example 1:

Input: wordlist = ["KiTe","kite","hare","Hare"], queries = ["kite","Kite","KiTe","Hare","HARE","Hear","hear","keti","keet","keto"]
Output: ["kite","KiTe","KiTe","Hare","hare","","","KiTe","","KiTe"]

Note:

• 1 <= wordlist.length <= 5000
• 1 <= queries.length <= 5000
• 1 <= wordlist[i].length <= 7
• 1 <= queries[i].length <= 7
• All strings in wordlist and queries consist only of english letters.

题目

给定一个单词字典list和一个查询列表，针对查询列表中的每一个单词word判断：

1. 如果大小写敏感，word是否在list中出现
2. 如果大小写不敏感，word是否在list中出现，返回第一个出现的单词
3. 如果大小写不敏感，且word中的元音字母可以任意替换其他的元音字母，转换后的word是否在list中出现，返回第一个出现的单词
4. 都不满足，返回空字符串

思路

对wordlist中的单词word进行预处理，维护三个HashMap：(word -> index)、(word.toLowerCase() -> index)、(word.toLowerCase().将所有元音字母转换为’#’() -> index)。预处理后，对每一个query按顺序处理并在三个HashMap中查找即可。

代码实现

Java

class Solution {
    public String[] spellchecker(String[] wordlist, String[] queries) {
        String[] ans = new String[queries.length];
        Map<String, Integer> origin = new HashMap<>();
        Map<String, Integer> lower = new HashMap<>();
        Map<String, Integer> trans = new HashMap<>();
        for (int i = 0; i < wordlist.length; i++) {
            String word = wordlist[i];
            origin.putIfAbsent(word, i);
            lower.putIfAbsent(word.toLowerCase(), i);
            trans.putIfAbsent(transform(word), i);
        }
        for (int i = 0; i < queries.length; i++) {
            String query1 = queries[i];
            if (origin.containsKey(query1)) {
                ans[i] = wordlist[origin.get(query1)];
                continue;
            }
            String query2 = query1.toLowerCase();
            if (lower.containsKey(query2)) {
                ans[i] = wordlist[lower.get(query2)];
                continue;
            }
            String query3 = transform(query1);
            if (trans.containsKey(query3)) {
                ans[i] = wordlist[trans.get(query3)];
                continue;
            }
            ans[i] = "";
        }
        return ans;
    }
    private String transform(String s) {
        s = s.toLowerCase();
        StringBuilder sb = new StringBuilder();
        for (char c : s.toCharArray()) {
            if (c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u') {
                sb.append('#');
            } else {
                sb.append(c);
            }
        }
        return sb.toString();
    }
}