LeetCode-in-Java

676. Implement Magic Dictionary

Medium

Design a data structure that is initialized with a list of different words. Provided a string, you should determine if you can change exactly one character in this string to match any word in the data structure.

Implement the MagicDictionary class:

• MagicDictionary() Initializes the object.
• void buildDict(String[] dictionary) Sets the data structure with an array of distinct strings dictionary.
• bool search(String searchWord) Returns true if you can change exactly one character in searchWord to match any string in the data structure, otherwise returns false.

Example 1:

Input

[“MagicDictionary”, “buildDict”, “search”, “search”, “search”, “search”] [[],

[[“hello”, “leetcode”]], [“hello”], [“hhllo”], [“hell”], [“leetcoded”]]

Output: [null, null, false, true, false, false]

Explanation:

MagicDictionary magicDictionary = new MagicDictionary(); 
magicDictionary.buildDict(["hello", "leetcode"]); 
magicDictionary.search("hello"); // return False 
magicDictionary.search("hhllo"); // We can change the second 'h' to 'e' to match "hello" so we return True 
magicDictionary.search("hell"); // return False 
magicDictionary.search("leetcoded"); // return False

Constraints:

• 1 <= dictionary.length <= 100
• 1 <= dictionary[i].length <= 100
• dictionary[i] consists of only lower-case English letters.
• All the strings in dictionary are distinct.
• 1 <= searchWord.length <= 100
• searchWord consists of only lower-case English letters.
• buildDict will be called only once before search.
• At most 100 calls will be made to search.

Solution

public class MagicDictionary {
    private String[] dictionaryWords;

    public MagicDictionary() {
        dictionaryWords = null;
    }

    public void buildDict(String[] dictionary) {
        dictionaryWords = dictionary;
    }

    public boolean search(String searchWord) {
        for (String word : dictionaryWords) {
            if (isOffByOneLetter(word, searchWord)) {
                return true;
            }
        }
        return false;
    }

    private boolean isOffByOneLetter(String word, String searchWord) {
        if (isDifferentLengths(word, searchWord) || word.equals(searchWord)) {
            return false;
        }
        int numDifferentLetters = 0;
        for (int i = 0; i < word.length(); i++) {
            if (isNotTheSameLetter(word.charAt(i), searchWord.charAt(i))) {
                numDifferentLetters++;
            }
            if (numDifferentLetters > 1) {
                return false;
            }
        }
        return numDifferentLetters == 1;
    }

    private boolean isDifferentLengths(String word, String searchWord) {
        return word.length() != searchWord.length();
    }

    private boolean isNotTheSameLetter(char c1, char c2) {
        return c1 != c2;
    }
}

/*
 * Your MagicDictionary object will be instantiated and called as such:
 * MagicDictionary obj = new MagicDictionary();
 * obj.buildDict(dictionary);
 * boolean param_2 = obj.search(searchWord);
 */

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