Given a string, we can “shift” each of its letter to its successive letter, for example: "abc" -> "bcd". We can keep “shifting” which forms the sequence:

"abc" -> "bcd" -> ... -> "xyz"

Given a list of strings which contains only lowercase alphabets, group all strings that belong to the same shifting sequence.


Input: ["abc", "bcd", "acef", "xyz", "az", "ba", "a", "z"],


Convert each string to its shifted counterpart which starts with 'a'. Strings with the same counterpart should be grouped together

class Solution(object):
    def groupStrings(self, strings):
        :type strings: List[str]
        :rtype: List[List[str]]
        if len(strings) == 0:
            return []

        str_map = dict()
        for s in strings:
            delta = ord(s[0]) - ord('a')
            k = "".join([chr(ord(c) - delta) if c >= s[0] else chr(26 + ord(c) - delta) for c in s])
            if k not in str_map:
                str_map[k] = list()

        return str_map.values()