leetcode: 49. Group Anagrams

# Given an array of strings, group anagrams together.
#
# For example, given: ["eat", "tea", "tan", "ate", "nat", "bat"],
# Return:
#
# [
#     ["ate", "eat","tea"],
#     ["nat","tan"],
#     ["bat"]
# ]
# Note: All inputs will be in lower-case.

class Solution():
    def groupAnagrams(self, x):
        d = {}
        for s in x:
            key = ''.join(sorted(s))
            if key in d:
                d[key].append(s)
            else:
                d[key] = [s]
        return list(d.values())


if __name__ == '__main__':
    strs = [["ate", "eat", "tea"], ["nat", "tan"], ["bat"]]
    assert Solution().groupAnagrams(strs) == [[['ate', 'eat', 'tea']], [['nat', 'tan']], [['bat']]]