[LeetCode-316] Remove Duplicate Letters

LeetCode-316

Remove Duplicate Letters : Given a string s, remove duplicate letters so that every letter appears once and only once. You must make sure your result is the smallest in lexicographical order among all possible results.

note :

Answer

        :::python

class Solution:
    def removeDuplicateLetters(self, s: str) -> str:
        for char in sorted(set(s)):
            suffix = s[s.index(char):]
            if set(s)==set(suffix):
                return char + self.removeDuplicateLetters(suffix.replace(char,''))
        return ''

Result : 55ms Memory: 14.1mb