Verifying an Alien Dictionary - LeetCode
In an alien language, surprisingly they also use english lowercase letters, but possibly in a different order. The…
In an alien language, surprisingly they also use english lowercase letters, but possibly in a different
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 lexicographicaly in this alien language.
Input: words = ["hello","leetcode"], order = "hlabcdefgijkmnopqrstuvwxyz"
Explanation: As 'h' comes before 'l' in this language, then the sequence is sorted.
Input: words = ["word","world","row"], order = "worldabcefghijkmnpqstuvxyz"
Explanation: As 'd' comes after 'l' in this language, then words > words, hence the sequence is unsorted.
Input: words = ["apple","app"], order = "abcdefghijklmnopqrstuvwxyz"
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).
1 <= words.length <= 100
1 <= words[i].length <= 20
order.length == 26
- All characters in
orderare English lowercase letters.
- create a map for alien alphbet orders
- scan throw the String, if we find any word bigger than the next word, return false. Else return true at the end
- Trick: be careful for the mapping, might get confuse
4. TC: O(n) — mapping is O(1); check the String length