[LeetCode] Problem 890 - Find and Replace Pattern

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You have a list of words and a pattern, and you want to know which words in words matches the pattern.

A word matches the pattern if there exists a permutation of letters p so that after replacing every letter x in the pattern with p(x), we get the desired word.

(Recall that a permutation of letters is a bijection from letters to letters: every letter maps to another letter, and no two letters map to the same letter.)

Return a list of the words in words that match the given pattern.

You may return the answer in any order.

Example

Input: words = [“abc”,”deq”,”mee”,”aqq”,”dkd”,”ccc”], pattern = “abb”

Output: [“mee”,”aqq”]

Explanation: “mee” matches the pattern because there is a permutation {a -> m, b -> e, …}.
“ccc” does not match the pattern because {a -> c, b -> c, …} is not a permutation,
since a and b map to the same letter.

Note

  • 1 <= words.length <= 50
  • 1 <= pattern.length = words[i].length <= 20

Code

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public List<String> findAndReplacePattern(String[] words, String pattern) {
    List<String> result = new ArrayList<>();

    for (String word : words) {
        if (match(word, pattern))
            result.add(word);
    }

    return result;
}

private boolean match(String word, String pattern) {
    int[] w = new int[26];
    int[] p = new int[26];
    Arrays.fill(w, -1);
    Arrays.fill(p, -1);

    for (int i = 0; i < pattern.length(); i++) {
        if (w[word.charAt(i) - 'a'] != p[pattern.charAt(i) - 'a'])
            return false;
        
        w[word.charAt(i) - 'a'] = p[pattern.charAt(i) - 'a'] = i;
    }

    return true;
}