group-anagram.py

from collections import defaultdict

class Solution:
    def groupAnagrams(self, strs: List[str]) -> List[List[str]]:
        anagrams = defaultdict(list)
        for st in strs:
            count = [0] * 26
            for c in st:
                count[ord(c) - ord('a')] += 1

            key = tuple(count)
            anagrams[key].append(st)

        return list(anagrams.values())