Verifying an Alien Dictionary

In an alien language, surprisingly, they also use English lowercase letters, but possibly in a different order. The order of the alphabet is some permutation of lowercase letters.

Given a sequence of words written in the alien language, and the order of the alphabet, return true if and only if the given words are sorted lexicographically in this alien language.

LeetCode Problem - 953

class Solution {
    // Map to store the custom order of characters according to the alien language
    Map<Character, Integer> map;

    public boolean isAlienSorted(String[] words, String order) {
        // Initialize the map with the order of characters in the alien language
        map = new HashMap<>();
        for (int i = 0; i < order.length(); i++) {
            map.put(order.charAt(i), i);
        }

        // Compare each word with the next one to ensure they are sorted
        for (int i = 0; i < words.length - 1; i++) {
            // If any pair of words is not sorted, return false
            if (!checkLexicographically(words[i], words[i + 1])) return false;
        }

        // If all words are sorted, return true
        return true;
    }

    // Helper function to compare two words lexicographically according to the alien language order
    public boolean checkLexicographically(String str1, String str2) {
        int lengthStr1 = str1.length();
        int lengthStr2 = str2.length();
        int minLength = Math.min(lengthStr1, lengthStr2);

        // Compare characters of both strings based on their custom order
        for (int i = 0; i < minLength; i++) {
            int char1Order = map.get(str1.charAt(i));
            int char2Order = map.get(str2.charAt(i));

            // If the first differing character in str1 is less, the pair is in order
            if (char1Order < char2Order) {
                return true;
            } 
            // If the first differing character in str1 is greater, the pair is not in order
            else if (char1Order > char2Order) {
                return false;
            }
        }

        // If all characters compared so far are equal, the shorter string should come first
        return lengthStr1 <= lengthStr2;
    }
}