966. Vowel Spellchecker

Description

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.
    <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>
    

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"]

Example 2:

Input: wordlist = ["yellow"], queries = ["YellOw"]
Output: ["yellow"]

 

Constraints:

  • 1 <= wordlist.length, queries.length <= 5000
  • 1 <= wordlist[i].length, queries[i].length <= 7
  • wordlist[i] and queries[i] consist only of only English letters.

Solutions

Solution 1

Python Code
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class Solution:
    def spellchecker(self, wordlist: List[str], queries: List[str]) -> List[str]:
        def f(w):
            t = []
            for c in w:
                t.append("*" if c in "aeiou" else c)
            return "".join(t)

        s = set(wordlist)
        low, pat = {}, {}
        for w in wordlist:
            t = w.lower()
            low.setdefault(t, w)
            pat.setdefault(f(t), w)

        ans = []
        for q in queries:
            if q in s:
                ans.append(q)
                continue
            q = q.lower()
            if q in low:
                ans.append(low[q])
                continue
            q = f(q)
            if q in pat:
                ans.append(pat[q])
                continue
            ans.append("")
        return ans

Java Code
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class Solution {
    public String[] spellchecker(String[] wordlist, String[] queries) {
        Set<String> s = new HashSet<>();
        Map<String, String> low = new HashMap<>();
        Map<String, String> pat = new HashMap<>();
        for (String w : wordlist) {
            s.add(w);
            String t = w.toLowerCase();
            low.putIfAbsent(t, w);
            pat.putIfAbsent(f(t), w);
        }
        int m = queries.length;
        String[] ans = new String[m];
        for (int i = 0; i < m; ++i) {
            String q = queries[i];
            if (s.contains(q)) {
                ans[i] = q;
                continue;
            }
            q = q.toLowerCase();
            if (low.containsKey(q)) {
                ans[i] = low.get(q);
                continue;
            }
            q = f(q);
            if (pat.containsKey(q)) {
                ans[i] = pat.get(q);
                continue;
            }
            ans[i] = "";
        }
        return ans;
    }

    private String f(String w) {
        char[] cs = w.toCharArray();
        for (int i = 0; i < cs.length; ++i) {
            char c = cs[i];
            if (c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u') {
                cs[i] = '*';
            }
        }
        return String.valueOf(cs);
    }
}

C++ Code
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class Solution {
public:
    vector<string> spellchecker(vector<string>& wordlist, vector<string>& queries) {
        unordered_set<string> s(wordlist.begin(), wordlist.end());
        unordered_map<string, string> low;
        unordered_map<string, string> pat;
        auto f = [](string& w) {
            string res;
            for (char& c : w) {
                if (c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u') {
                    res += '*';
                } else {
                    res += c;
                }
            }
            return res;
        };
        for (auto& w : wordlist) {
            string t = w;
            transform(t.begin(), t.end(), t.begin(), ::tolower);
            if (!low.count(t)) {
                low[t] = w;
            }
            t = f(t);
            if (!pat.count(t)) {
                pat[t] = w;
            }
        }
        vector<string> ans;
        for (auto& q : queries) {
            if (s.count(q)) {
                ans.emplace_back(q);
                continue;
            }
            transform(q.begin(), q.end(), q.begin(), ::tolower);
            if (low.count(q)) {
                ans.emplace_back(low[q]);
                continue;
            }
            q = f(q);
            if (pat.count(q)) {
                ans.emplace_back(pat[q]);
                continue;
            }
            ans.emplace_back("");
        }
        return ans;
    }
};

Go Code
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func spellchecker(wordlist []string, queries []string) (ans []string) {
	s := map[string]bool{}
	low := map[string]string{}
	pat := map[string]string{}
	f := func(w string) string {
		res := []byte(w)
		for i := range res {
			if res[i] == 'a' || res[i] == 'e' || res[i] == 'i' || res[i] == 'o' || res[i] == 'u' {
				res[i] = '*'
			}
		}
		return string(res)
	}
	for _, w := range wordlist {
		s[w] = true
		t := strings.ToLower(w)
		if _, ok := low[t]; !ok {
			low[t] = w
		}
		if _, ok := pat[f(t)]; !ok {
			pat[f(t)] = w
		}
	}
	for _, q := range queries {
		if s[q] {
			ans = append(ans, q)
			continue
		}
		q = strings.ToLower(q)
		if s, ok := low[q]; ok {
			ans = append(ans, s)
			continue
		}
		q = f(q)
		if s, ok := pat[q]; ok {
			ans = append(ans, s)
			continue
		}
		ans = append(ans, "")
	}
	return
}