953. Verifying an Alien Dictionary

📋 Đề Bài

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.

Example 1:

Input: words = ["hello","leetcode"], order = "hlabcdefgijkmnopqrstuvwxyz"
Output: true
Explanation: As 'h' comes before 'l' in this language, then the sequence is sorted.

Example 2:

Input: words = ["word","world","row"], order = "worldabcefghijkmnpqstuvxyz"
Output: false
Explanation: As 'd' comes after 'l' in this language, then words[0] > words[1], hence the sequence is unsorted.

Example 3:

Input: words = ["apple","app"], order = "abcdefghijklmnopqrstuvwxyz"
Output: false
Explanation: The first three characters "app" match, and the second string is shorter (in size.) According to lexicographical rules "apple" > "app", because 'l' > '∅', where '∅' is defined as the blank character which is less than any other character (More info).

Constraints:

1 <= words.length <= 100
1 <= words[i].length <= 20
order.length == 26
All characters in words[i] and order are English lowercase letters.

🧠 Thuật Toán & Kỹ Thuật

Sorting (Sắp xếp)

⏱️ Thời gian O(n²)

💾 Không gian O(n)

💻 Lời Giải

Python 0953-verifying-an-alien-dictionary.py

class Solution:
    def isAlienSorted(self, words: List[str], order: str) -> bool:
        n = len(words)
        h = {}
        
        for i, char in enumerate(order):
            h[char] = chr(i + ord('a'))
            
        words = [[h[char] for char in word] for word in words]
        
        for word1, word2 in zip(words, words[1:]):
            if word1 > word2:
                return False
            
        return True