An extraterrestrial language uses the English alphabet, but the letter order is unknown. A list of strings words is provided, which represents words from the extraterrestrial language's dictionary, and it is claimed that these words are sorted according to the new language's lexicographical order.
If this claim is false, and the arrangement of strings in words cannot match any possible letter order, return an empty string. Otherwise, return a string containing the unique letters of the extraterrestrial language sorted according to the language's rules. If multiple valid solutions exist, any of them are acceptable.
words: string[]: An array of strings where each string is a word in the extraterrestrial languageInput: words = ["cab","abc","bca"]Output: "cab"Explanation: Comparing 'cab' and 'abc', the first differing characters are c and a, suggesting c comes before a. Comparing 'abc' and 'bca', the first differing characters are a and b, so a comes before b. Thus, the order of letters in the new alphabet is 'cab'.
Input: words = ["abc","ab"]Output: ""Explanation: The list is invalid because 'ab' should not come before 'abc'. A shorter word with the same prefix cannot appear after a longer word, so the sequence is impossible, and the result is an empty string.
Input: words = ["z","x","z"]Output: ""Explanation: The sequence is invalid because 'z' appears both before and after 'x', which creates a contradiction in the order. This inconsistency makes it impossible to deduce a valid letter order, so the result is an empty string.
words.length <= 100words[i].length <= 10words[i] consists of only lowercase English lettersAn extraterrestrial language uses the English alphabet, but the letter order is unknown. A list of strings words is provided, which represents words from the extraterrestrial language's dictionary, and it is claimed that these words are sorted according to the new language's lexicographical order.
If this claim is false, and the arrangement of strings in words cannot match any possible letter order, return an empty string. Otherwise, return a string containing the unique letters of the extraterrestrial language sorted according to the language's rules. If multiple valid solutions exist, any of them are acceptable.
words: string[]: An array of strings where each string is a word in the extraterrestrial languageInput: words = ["cab","abc","bca"]Output: "cab"Explanation: Comparing 'cab' and 'abc', the first differing characters are c and a, suggesting c comes before a. Comparing 'abc' and 'bca', the first differing characters are a and b, so a comes before b. Thus, the order of letters in the new alphabet is 'cab'.
Input: words = ["abc","ab"]Output: ""Explanation: The list is invalid because 'ab' should not come before 'abc'. A shorter word with the same prefix cannot appear after a longer word, so the sequence is impossible, and the result is an empty string.
Input: words = ["z","x","z"]Output: ""Explanation: The sequence is invalid because 'z' appears both before and after 'x', which creates a contradiction in the order. This inconsistency makes it impossible to deduce a valid letter order, so the result is an empty string.
words.length <= 100words[i].length <= 10words[i] consists of only lowercase English lettersconsole.log() statements will appear here.